#/usr/bin/tclsh
# ^^^ help out editors which guess this file's content type.
#
# This is the main autosetup-compatible configure script for the
# SQLite project.
#
# This script should be kept compatible with JimTCL, a copy of which
# is included in this source tree as ./autosetup/jimsh0.c. The number
# of incompatibilities between canonical TCL and JimTCL is very low
# and alternative formulations of incompatible constructs have, so
# far, been easy to find.
#
# JimTCL: https://jim.tcl.tk
#
use cc cc-db cc-shared cc-lib proj pkg-config

# $DUMP_DEFINES_TXT is the file emitted by --dump-defines, intended
# only for build debugging and not part of the public build interface.
set DUMP_DEFINES_TXT ./config.defines.txt
# $DUMP_DEFINES_JSON is the autosetup counterpart of the historical
# "DEFS" var which was generated by the autotools in the pre-processed
# autotools builds (but not in the canonical tree). This is used by at
# least one high-profile client to extract build config info for use
# in compiling a scripting-language binding, so its name should not be
# arbitrarily changed.
#
# 2024-10-26: generation of this file is disabled (via an empty file
# name) until/unless someone voices a specific interest in it. The
# original motivating use case is handled fine by sqlite_cfg.h.
set DUMP_DEFINES_JSON ""; #./config.defines.json

########################################################################
# Regarding flag compatibility with the historical autotool configure
# script:
#
# A very long story made short, autosetup's --flag handling has
# some behaviors which make it impossible to implement 100% identical
# flags compared to the historical autotools build. The differences
# are documented here:
#
# 1) --debug is used by autosetup itself, so we have to rename it to
# --with-debug. We cannot use --enable-debug because that is, for
# autosetup, and alias for --debug=1.
#
# 2) In autosetup, all flags starting with (--enable, --disable) are
# forced to be booleans and receive special handling in how they're
# resolved. Because of that we have to rename:
#
#   2.1) --enable-tempstore[=no] to --with-tempstore[=no].
#
########################################################################
# A gentle introduction to flags handling in autosetup
#
# Reference: https://msteveb.github.io/autosetup/developer/
#
# All configure flags must be described in an 'options' call, which
# must appear very early on in this script. The general syntax is:
#
#  FLAG => {Help text}
#
# Where FLAG can have any of the following formats:
#
#   boolopt            => "a boolean option which defaults to disabled"
#   boolopt2=1         => "a boolean option which defaults to enabled"
#   stringopt:         => "an option which takes an argument, e.g. --stringopt=value"
#   stringopt2:=value  => "an option where the argument is optional and defaults to 'value'"
#   optalias booltopt3 => "a boolean with a hidden alias. --optalias is not shown in --help"
#
# Autosetup does no small amount of specialized handling for flags,
# especially booleans. Each bool-type --FLAG implicitly gets
# --enable-FLAG and --disable-FLAG forms, and explicitly adding flags
# with those prefixes will force them to be boolean flags. e.g. we
# define a flag "readline", which will be interpreted in one of two
# ways, depending on how it's invoked and how its default is defined:
#
#   --enable-readline ==> boolean true
#   --disable-readline ==> boolean false
#
# Trying to pass --readline or --readline=1 or --readline=0 will
# result in an "unrecognized option" error, despite the the options
# call listing the flag as "readline".
#
# The behavior described above can lead lead to some confusion when
# writing help text. For example:
#
#   options { json=1 {Disable JSON functions} }
#
# The reason the help text says "disable" is because a boolean option
# defaulting to true is, in the --help text, rendered as:
#
#   --disable-json          Disable JSON functions
#
# Whereas a bool flag which defaults to false will instead render as:
#
#   --enable-FLAG
#
# Non-boolean flags, in contrast, use the names specifically given to
# them in the 'options' invocation. e.g. "with-tcl" is the --with-tcl
# flag. Autosetup may, however, choose to automatically alter the help
# text, as demonstrated here:
#
#   options {
#    readline=1           => {Disable readline support}
#    with-readline-lib:   => {Readline library}
#    with-readline-inc:   => {Readline include paths}
#   }
#
#   $ ./configure --help | grep readline
#   --disable-readline      disable readline support
#   --with-readline-lib     specify readline library
#   --with-readline-inc     specify readline include paths
#
# Note that it prefixed and lower-case the help message. Whether
# that's a feature or a bug can be debated.
#
# Fetching values for flags:
#
#   booleans: use one of:
#     - [opt-bool FLAG] is autosetup's built-in command for this, but we
#       have some convenience variants:
#     - [proj-opt-truthy FLAG]
#     - [proj-opt-if-truthy FLAG {THEN} {ELSE}]
#
#   Non-boolean (i.e. string) flags:
#     - [opt-val FLAG ?default?]
#
########################################################################
set flags {
  # <build-modes>
  with-debug:=1        => {Enable debug build flags}
  shared=1             => {Disable build of shared libary}
  static=1             => {Disable build of static library (mostly)}
  amalgamation=1       => {Disable the amalgamation and instead build all files separately.}
  # </build-modes>
  # <lib-feature>
  threadsafe=1         => {Disable mutexing}
  with-tempstore:=no   => {Use an in-ram database for temporary tables: never,no,yes,always}
  largefile=1          => {Disable large file support}
  load-extension=1     => {Disable loading of external extensions}
  math=1               => {Disable math functions}
  json=1               => {Disable JSON functions}
  all                  => {Enable FTS4, FTS5, Geopoly, RTree, Sessions}
  memsys5              => {Enable MEMSYS5}
  memsys3              => {Enable MEMSYS3}
  fts3                 => {Enable the FTS3 extension}
  fts4                 => {Enable the FTS4 extension}
  fts5                 => {Enable the FTS5 extension}
  update-limit         => {Enable the UPDATE/DELETE LIMIT clause}
  geopoly              => {Enable the GEOPOLY extension}
  rtree                => {Enable the RTREE extension}
  session              => {Enable the SESSION extension}
  # </lib-feature>
  # <tcl>
  with-tclsh:PATH      => {Full pathname of tclsh to use}
  with-tcl:DIR         => {Directory containing tclConfig.sh}
  tcl=1                => {Disable components which require TCL-dev}
  # <tcl>
  # <line-editing>
  readline=1           => {Disable readline support}
  # --with-readline-lib is a backwards-compatible alias for
  # --with-readline-ldflags
  with-readline-lib:
  with-readline-ldflags:=auto
                     => {Readline LDFLAGS, e.g. -lreadline -lncurses}
  # --with-readline-inc is a backwards-compatible alias for
  # --with-readline-cflags
  with-readline-inc:
  with-readline-cflags:=auto
                       => {Readline CFLAGS, e.g. -I/path/to/includes}
  with-readline-header:PATH
                       => {Full path to readline.h, from which --with-readline-cflags will be derived}
  with-linenoise:DIR   => {Source directory for linenoise.c and linenoise.h}
  editline=0           => {BSD editline support}
  # </line-editing>
  # <icu>
  with-icu-ldflags:LDFLAGS
                        => {Enable SQLITE_ENABLE_ICU and add the given linker flags for the ICU libraries}
  icu-collations=0      => {Enable SQLITE_ENABLE_ICU_COLLATIONS. Requires --with-icu-ldflags=...}
  with-icu-config:=auto => {Enable SQLITE_ENABLE_ICU and fetch linker flags from the given icu-config binary}
  # </icu>
  # <alternative-builds>
  with-wasi-sdk:=/opt/wasi-sdk
                       => {Top-most dir of the wasi-sdk for a WASI build}
  with-emsdk:DIR       => {Top-most dir of the Emscripten SDK installation}
  # </alternative-builds>
  # <developer>
  test-status          => {Enable status of tests}
  gcov=0               => {Enable coverage testing using gcov}
  linemacros           => {Enable #line macros in the amalgamation.}
  dump-defines=0       => {Dump autosetup defines to $DUMP_DEFINES_TXT (for build debugging)}
  # </developer>
}
if {"" ne $DUMP_DEFINES_JSON} {
  lappend flags \
    defines-json-include-lowercase=0 \
    => {Include lower-case defines (primarily system paths) in $DUMP_DEFINES_JSON}
}
options [subst $flags]
unset flags

#
# Carry values from hidden --flag aliases over to their canonical flag
# forms.
#
proj-xfer-options-aliases {
  with-readline-inc => with-readline-cflags
  with-readline-lib => with-readline-ldflags
}

set srcdir $::autosetup(srcdir)
set top_srcdir [get-define abs_top_srcdir]
set PACKAGE_VERSION [readfile $srcdir/VERSION]
define PACKAGE_NAME "sqlite"
define PACKAGE_URL {https://sqlite.org}
define PACKAGE_VERSION $PACKAGE_VERSION
define PACKAGE_STRING "[get-define PACKAGE_NAME] $PACKAGE_VERSION"
define PACKAGE_BUGREPORT [get-define PACKAGE_URL]/forum

msg-result "srcdir = $srcdir"
msg-result "top_srcdir = $top_srcdir"
msg-result [proj-bold "Configuring SQLite version $PACKAGE_VERSION"]

#
# SQLITE_AUTORECONFIG contains make target rules for re-running the
# configure script with the same arguments it was initially invoked
# with. This can be used to automatically reconfigure
#
define-append SQLITE_AUTORECONFIG cd '$::autosetup(builddir)' && '$top_srcdir/configure'
#{*}$::autosetup(argv) breaks with --flag='val with spaces', so...
foreach arg $::autosetup(argv) {
  define-append SQLITE_AUTORECONFIG '$arg'
}


# Are we cross-compiling?
set cross_compiling [proj-is-cross-compiling]
if {![file exists sqlite3.pc.in]} {
  msg-result "This appears to be an out-of-tree build."
}

cc-check-tools ld ar

define OPT_FEATURE_FLAGS {} ; # -DSQLITE_OMIT/ENABLE flags.
define OPT_SHELL {}         ; # CFLAGS for the sqlite3 CLI app
########################################################################
# Adds $args, if not empty, to OPT_FEATURE_FLAGS.
# If the first arg is -shell then it strips that arg
# and passes the remaining args th sqlite-add-shell-opt
# before adding them to OPF_FEATURE_FLAGS.
proc sqlite-add-feature-flag {args} {
  set shell ""
  if {"-shell" eq [lindex $args 0]} {
    set args [lassign $args shell]
  }
  if {"" ne $args} {
    if {"" ne $shell} {
      sqlite-add-shell-opt {*}$args
    }
    define-append OPT_FEATURE_FLAGS {*}$args
  }
}
# Appends $args, if not empty, to OPT_SHELL.
proc sqlite-add-shell-opt {args} {
  if {"" ne $args} {
    define-append OPT_SHELL {*}$args
  }
}

proj-file-extensions
if {".exe" eq [get-define TARGET_EXEEXT]} {
  define SQLITE_OS_UNIX 0
  define SQLITE_OS_WIN 1
  # todo? add -DSQLITE_OS_WIN=1 to CFLAGS or CFLAGS_sqlite3_os?
} else {
  define SQLITE_OS_UNIX 1
  define SQLITE_OS_WIN 0
  # todo? add -DSQLITE_OS_UNIX=1 to CFLAGS or CFLAGS_sqlite3_os
}

#########
# Programs needed
if {"" eq [proj-bin-define install]} {
  proj-warn "Cannot find install binary, so 'make install' will not work."
  # Reminder: we historically have ./install-sh in the source tree.
  # Can we not simply use that?
  #
  # define BIN_INSTALL "$top_srcdir/install-sh"
  #
  # Nope: it MOVES its source files over the target, which breaks the
  # installation in some cases, e.g. when libtclsqlite3.so is built in
  # response to 'make install' and libsqlite3.a is moved before
  # libtclsqlite3.so is linked.  It's easy to hack to use cp instead
  # of mv (simply replace the instcmd=... bit) but that won't retain
  # the source timestamp and permissions unless we use cp's -p flag,
  # which may not be portable enough.
}

########################################################################
# We differentiate between two C compilers: the one used for binaries
# which are to run on the build system (BUILD_CC, a.k.a. BCC) and the
# one used for compiling binaries for the target system (CC,
# a.k.a. TCC).  Normally they're the same, but they will differ when
# cross-compiling.
define BUILD_CC [get-define CC_FOR_BUILD]
define BUILD_CFLAGS [get-env BUILD_CFLAGS {-g}]

########################################################################
# Handle --with-wasi-sdk=DIR
#
# This must be early because it may change the toolchain and disable
# several config options.
proc sqlite-check-wasi-sdk {} {
  set wasiSdkDir [opt-val with-wasi-sdk] ; # ??? [lindex [opt-val with-wasi-sdk] end]
  define HAVE_WASI_SDK 0
  #puts "x wasiSdkDir=$wasiSdkDir foo=[lindex [opt-val with-wasi-sdk] end]"
  if {$wasiSdkDir eq ""} {
    return 0
  } elseif {$::cross_compiling} {
    proj-fatal "Cannot combine --with-wasi-sdk with cross-compilation"
  }
  msg-result "Checking WASI SDK directory \[$wasiSdkDir]... "
  #puts "prefix = [prefix $wasiSdkDir/bin {clang ld}]"
  proj-affirm-files-exist -v {*}[prefix "$wasiSdkDir/bin/" {clang wasm-ld}]
  msg-result "Using wasi-sdk clang, disabling: tcl, CLI shell, DLL, loadable extensions, threading"
  define HAVE_WASI_SDK 1
  define WASI_SDK_DIR $wasiSdkDir
  proj-opt-set load-extension 0 ;# ==> --disable-load-extension
  proj-opt-set threadsafe 0     ;# ==> --threadsafe=0
  proj-opt-set tcl 0            ;# ==> --disable-tcl
  proj-opt-set shared 0         ;# ==> --disable-shared
  set cross_compiling 1

  # Changing --host and --target have no effect here except to possibly
  # cause confusion. autoconf has finished processing them by this
  # point.
  #
  #  host_alias=wasm32-wasi
  #  target=wasm32-wasi
  #
  # Merely changing CC and LD to the wasi-sdk's is enough to get
  # sqlite3.o building in WASM format.
  # XXX CC="${wasiSdkDir}/bin/clang"
  # XXX LD="${wasiSdkDir}/bin/wasm-ld"
  # XXX RANLIB="${wasiSdkDir}/bin/llvm-ranlib"
  define CC "${wasiSdkDir}/bin/clang"
  define LD "${wasiSdkDir}/bin/wasm-ld"
  #define STRIP "${wasiSdkDir}/bin/strip"
  return 1
}; # sqlite-check-wasi-sdk
sqlite-check-wasi-sdk

#
# Enable large file support (if special flags are necessary)
define HAVE_LFS 0
if {[opt-bool largefile]} {
  cc-check-lfs
}

#
# Check for needed/wanted data types
cc-with {-includes stdint.h} \
  {cc-check-types int8_t int16_t int32_t int64_t intptr_t \
     uint8_t uint16_t uint32_t uint64_t uintptr_t}

#
# Check for needed/wanted functions
cc-check-functions gmtime_r isnan localtime_r localtime_s \
  malloc_usable_size strchrnul usleep utime pread pread64 pwrite pwrite64

proj-check-function-in-lib fdatasync rt
define LDFLAGS_FDATASYNC [get-define lib_fdatasync]
undefine lib_fdatasync

#
# Check for needed/wanted headers
cc-check-includes \
  sys/types.h sys/stat.h dlfcn.h unistd.h \
  stdlib.h malloc.h memory.h \
  string.h strings.h \
  inttypes.h

# These are optional for JimTCL but necessary if we want to use it for
# code generation:
cc-check-includes dirent.h sys/time.h

if {[cc-check-includes zlib.h] && [proj-check-function-in-lib deflate z]} {
  # TODO: port over the more sophisticated zlib search from the fossil auto.def
  define HAVE_ZLIB 1; # "-DSQLITE_HAVE_ZLIB=1"
  define LDFLAGS_ZLIB -lz
  # Note that -DSQLITE_HAVE_ZLIB=1 is handled separately from the
  # other feature flags in the autotools build. Do we need to emulate
  # that?
  sqlite-add-shell-opt -DSQLITE_HAVE_ZLIB=1
} else {
  define HAVE_ZLIB 0
  define LDFLAGS_ZLIB ""
}

#
# Determine proper rpath-handling flags.
#
proj-check-rpath

proj-define-if-opt-truthy shared ENABLE_SHARED \
  "Build shared library?"

if {![proj-define-if-opt-truthy static ENABLE_STATIC \
        "Build static library?"]} {
  proj-warn "static lib build may be implicitly re-activated by other components, e.g. libtclsqlite3."
}

proj-define-if-opt-truthy amalgamation USE_AMALGAMATION \
  "Use amalgamation for builds?"

proj-define-if-opt-truthy gcov USE_GCOV "Use gcov?"

proj-define-if-opt-truthy test-status TSTRNNR_OPTS \
  "test-runner flags:" {--status} {}

proj-define-if-opt-truthy linemacros AMALGAMATION_LINE_MACROS \
  "Use #line macros in the amalgamation:"

msg-checking "Debug build? "

proj-if-opt-truthy with-debug {
  define SQLITE_DEBUG 1
  define TARGET_DEBUG {-g -DSQLITE_DEBUG=1 -DSQLITE_ENABLE_SELECTTRACE -DSQLITE_ENABLE_WHERETRACE -O0 -Wall}
  msg-result yes
} {
  define TARGET_DEBUG {-DNDEBUG}
  msg-result no
}

########################################################################
# TCL...
#
# sqlite-check-tcl performs most of the --with-tcl and --with-tclsh
# handling. Some related bits and pieces are performed before and
# after that function is called.
#
# Important [define]'d vars:
#
#  - HAVE_TCL indicates whether we have a tclsh suitable for building
#    the TCL SQLite extension and, by extension, the testing
#    infrastructure. This must only be 1 for environments where
#    tclConfig.sh can be found.
#
#  - TCLSH_CMD is the path to the canonical tclsh or "". It never
#    refers to jimtcl.
#
#  - TCL_CONFIG_SH is the path to tclConfig.sh or "".
#
#  - TCLLIBDIR is the dir to which libtclsqlite3 gets installed.
#
#  - TCLLIB_RPATH = the -rpath flag specific to libtclsqlite3, which
#    will usually differ from the rpath used by the rest of the lib.
#
#  - BTCLSH = the path to the tcl interpreter used for in-tree code
#    generation.  It may be jimtcl or the canonical tclsh but may not
#    be empty - this tree requires TCL to generated numerous
#    components.
#
define TCLSH_CMD {exit 1}
define HAVE_TCL 0
proc sqlite-check-tcl {} {
  # TODO: document the steps this is taking.
  if {![opt-bool tcl]} {
    msg-result "TCL disabled via --disable-tcl"
    define HAVE_TCL 0
    return
  }

  global top_srcdir
  msg-result "Checking for a suitable tcl... "
  set optTcl [proj-opt-truthy tcl]
  set use_tcl $optTcl
  set with_tclsh [opt-val with-tclsh]
  set with_tcl [opt-val with-tcl]
  #puts "sqlite-check-tcl: use_tcl ${use_tcl}"
  #puts "sqlite-check-tcl: with_tclsh=${with_tclsh}"
  #puts "sqlite-check-tcl: with_tcl=$with_tcl"
  if {"" eq $with_tclsh && "" eq $with_tcl} {
    set with_tclsh [proj-first-bin-of tclsh9.0 tclsh8.6 tclsh]
  }
  #puts "sqlite-check-tcl: with_tclsh=${with_tclsh}"

  if {"" ne $with_tclsh} {
    if {![file isfile $with_tclsh]} {
      proj-fatal "TCL shell $with_tclsh is not a file"
    } elseif {![file-isexec $with_tclsh]} {
      proj-fatal "TCL shell $with_tclsh is not executable"
    } else {
      define TCLSH_CMD $with_tclsh
      msg-result "Using tclsh: $with_tclsh"
    }
    if {$use_tcl} {
      if {[catch {exec $with_tclsh $top_srcdir/tool/find_tclconfig.tcl} result] == 0} {
        set with_tcl $result
      }
      if {"" ne $with_tcl && [file isdir $with_tcl]} {
        msg-result "$with_tclsh recommends the tclConfig.sh from $with_tcl"
      } else {
        proj-warn "$with_tclsh is unable to recommand a tclConfig.sh"
        set use_tcl 0
      }
    }
  }

  set cfg ""
  set tclSubdirs {tcl9.0 tcl8.6 lib}
  while {1} {
    if {$use_tcl} {
      if {"" ne $with_tcl} {
        if {[file readable "${with_tcl}/tclConfig.sh"]} {
          set cfg "${with_tcl}/tclConfig.sh"
        } else {
          foreach i $tclSubdirs {
            if {[file readable "${with_tcl}/$i/tclConfig.sh"]} {
              set cfg "${with_tcl}/$i/tclConfig.sh"
              break
            }
          }
        }
        if {"" eq $cfg} {
          proj-fatal "No tclConfig.sh found under ${with_tcl}"
        }
      } else {
        # If we have not yet found a tclConfig.sh file, look in $libdir which is
        # set automatically by autosetup or by the --prefix command-line option.
        # See https://sqlite.org/forum/forumpost/e04e693439a22457
        set libdir [get-define libdir]
        if {[file readable "${libdir}/tclConfig.sh"]} {
          set cfg "${libdir}/tclConfig.sh"
        } else {
          foreach i $tclSubdirs {
            if {[file readable "${libdir}/$i/tclConfig.sh"]} {
              set cfg "${libdir}/$i/tclConfig.sh"
              break
            }
          }
        }
        if {![file readable $cfg]} {
          proj-indented-notice {
            WARNING: Cannot find a usable tclConfig.sh file.  Use
            --with-tcl=DIR to specify a directory where tclConfig.sh
            can be found.  SQLite does not use TCL internally, but TCL
            is required for testing.
          }
          break
        }
      }
      msg-result "Using tclConfig.sh: $cfg"
    } elseif {!$optTcl} {
      proj-warn "Unable to run tests because of --disable-tcl"
    } else {
      proj-warn "Unable to run tests because no tclConfig.sh file could be located"
    }
    break
  }

  define TCL_CONFIG_SH $cfg
  # The historical configure.ac sources tclConfig.sh so that it can
  # use the several TCL_... env vars. We obviously cannot do that from
  # TCL, so we apply a level of indirection which sources that script
  # then emits the pieces we're interested in as TCL code. If the
  # config is not available, this emits empty-string entries for the
  # various options we're interested in.
  eval [exec "${top_srcdir}/tool/tclConfigShToTcl.sh" "[get-define TCL_CONFIG_SH]"]

  if {"" eq $with_tclsh} {
    set with_tclsh [get-define TCL_EXEC_PREFIX]/bin/tclsh[get-define TCL_VERSION]
    if {![file-isexec $with_tclsh]} {
      set with_tclsh2 [get-define TCL_EXEC_PREFIX]/bin/tclsh
      if {![file-isexec $with_tclsh2]} {
        proj-warn "Cannot find a usable tclsh (tried: $with_tclsh $with_tclsh2)"
      } else {
        set with_tclsh $with_tclsh2
      }
    }
  }
  define TCLSH_CMD $with_tclsh

  if {$use_tcl} {
    # Set up the TCLLIBDIR and TCLLIB_RPATH
    set tcllibdir [get-env TCLLIBDIR ""]
    if {"" eq $tcllibdir} {
      if {[catch {exec echo "puts stdout \$auto_path" | "$with_tclsh"} result] == 0} {
        foreach i $result {
          if {[file isdir $i]} {
            set tcllibdir $i
            break
          }
        }
      } else {
        proj-warn "Cannot determine TCLLIBDIR"
      }
    }
    set tclrpath ""
    if {"" ne $tcllibdir} {
      set tcllibdir "${tcllibdir}/sqlite3"
      set rp [get-define SH_LINKRPATH]
      set tclrpath [string map [list "%s" $tcllibdir] $rp]
      # Reminder: tclConfig.sh has TCL_LD_SEARCH_FLAGS to set the
      # rpath but (A) it includes an unexpand var ref to
      # ${LIB_RUNTIME_DIR}, which must be set in the makefile and (B)
      # that flag is inherently compiler-dependent so it's not as
      # portable as tclConfig.sh assumes. We'll instead use the rpath
      # flag which autosetup determines for the current compiler.
    }
    define TCLLIBDIR $tcllibdir
    define TCLLIB_RPATH $tclrpath
    #proj-fatal "TCLLIB_RPATH = [get-define TCLLIB_RPATH]"
  } else {
    define TCLLIBDIR ""
    define TCLLIB_RPATH ""
  }

  if {[file exists $with_tclsh]} {
    msg-result "Using tclsh: $with_tclsh"
    define HAVE_TCL 1
  } else {
    proj-warn "Cannot find a usable tclsh, so cannot run tests."
  }
}; # sqlite-check-tcl

sqlite-check-tcl

########################################################################
# Check which TCL to use as a code generator. Prefer jimsh simply
# because we have it in-tree (it's part of autosetup).
#
# Building jimsh0.c with -DJIM_COMPAT changes certain behavior to be
# compatible with canonical TCL. Specifically: jim's [expr] only
# accepts one arg unless JIM_COMPAT is defined. As of 2024-10-23,
# jimsh0.c defines JIM_COMPAT automatically (prior to that it intended
# to but a typo of JIM_TCL_COMPAT made it a no-op).
define CFLAGS_JIMSH {}
msg-result "Which TCL to use for code generation... "
set cgtcl [opt-val with-tclsh jimsh]
if {"jimsh" ne $cgtcl} {
  # When --with-tclsh=X is used, use that for all TCL purposes,
  # including in-tree code generation, per developer request.
  define BTCLSH "\$(TCLSH_CMD)"
} else {
  if {[cc-check-functions realpath]} {
    define-append CFLAGS_JIMSH -DHAVE_REALPATH
    define BTCLSH "\$(JIMSH)"
  } elseif {[cc-check-functions _fullpath]} {
    # _fullpath() is a Windows API
    define-append CFLAGS_JIMSH -DHAVE__FULLPATH
    define BTCLSH "\$(JIMSH)"
  } elseif {[file exists [get-define TCLSH_CMD]]} {
    set cgtcl [get-define TCLSH_CMD]
    define BTCLSH "\$(TCLSH_CMD)"
  } else {
    # One last-ditch effort to find TCLSH_CMD: use info from
    # tclConfig.sh to try to find a tclsh
    if {"" eq [get-define TCLSH_CMD]} {
      set tpre [get-define TCL_EXEC_PREFIX]
      if {"" ne $tpre} {
        set tv [get-define TCL_VERSION]
        if {[file-isexec "${tpre}/bin/tclsh${tv}"]} {
          define TCLSH_CMD "${tpre}/bin/tclsh${tv}"
        } elseif {[file-isexec "${tpre}/bin/tclsh"]} {
          define TCLSH_CMD "${tpre}/bin/tclsh"
        }
        unset tv
      }
      unset tpre
    }
    set cgtcl [get-define TCLSH_CMD]
    if {![file exists $cgtcl]} {
      proj-fatal "Cannot find a tclsh to use for code generation."
    }
    define BTCLSH "\$(TCLSH_CMD)"
  }
}
msg-result "TCL for code generation: $cgtcl"
unset cgtcl
#define CFLAGS_JIMSH {-DJUST_TESTING}

# /TCL
########################################################################

########################################################################
# Thread safety?
msg-checking "Support threadsafe operation? "
proj-if-opt-truthy threadsafe {
  msg-result yes
  sqlite-add-feature-flag -DSQLITE_THREADSAFE=1
  if {![proj-check-function-in-lib pthread_create pthread]
      || ![proj-check-function-in-lib pthread_mutexattr_init pthread]} {
    user-error "Missing required pthread bits"
  }
  define LDFLAGS_PTHREAD [get-define lib_pthread_create]
  undefine lib_pthread_create
} {
  msg-result no
  sqlite-add-feature-flag -DSQLITE_THREADSAFE=0
  define LDFLAGS_PTHREAD ""
}

########################################################################
# Do we want temporary databases in memory?
#
if {1} {
  set ts [opt-val with-tempstore no]
  set tsn 1
  msg-checking "Use an in-ram database for temporary tables? "
  switch -- $ts {
    never  { set tsn 0 }
    no     { set tsn 1 }
    yes    { set tsn 2 }
    always { set tsn 3 }
    default {
      user-error "Invalid with-tempstore value \[$ts]. Use one of: never, no, yes, always"
    }
  }
  msg-result $ts
  define TEMP_STORE $tsn
  unset ts tsn
}

########################################################################
# sqlite-check-line-editing jumps through proverbial hoops to try to
# find a working line-editing library, setting:
#
#   - HAVE_READLINE to 0 or 1
#   - HAVE_LINENOISE to 0 or 1
#   - HAVE_EDITLINE to 0 or 1
#
# Only one of ^^^ those will be set to 1.
#
#   - LDFLAGS_READLINE = linker flags or empty string
#
#   - CFLAGS_READLINE = compilation flags for clients or empty string
#
# Note that LDFLAGS_READLINE and CFLAGS_READLINE may refer to
# linenoise or editline, not necessarily libreadline.
#
# Returns a string describing which line-editing approach to use, or
# "none" if no option is available.
proc sqlite-check-line-editing {} {
  msg-result "Checking for line-editing capability..."
  define HAVE_READLINE 0
  define HAVE_LINENOISE 0
  define HAVE_EDITLINE 0
  define LDFLAGS_READLINE ""
  define CFLAGS_READLINE ""
  set check [opt-val with-linenoise]
  if {"" ne $check} {
    # Use linenoise...
    set dirLn $check
    if {![file isdir $dirLn]} {
      proj-fatal "--with-linenoise value is not a directory"
    } elseif {![file exists $dirLn/linenoise.c] } {
      proj-fatal "Cannot find linenoise.c in $dirLn"
    } elseif {![file exists $dirLn/linenoise.h] } {
      proj-fatal "Cannot find linenoise.h in $dirLn"
    }
    msg-result "Using linenoise from $dirLn"
    define CFLAGS_READLINE "-I$dirLn $dirLn/linenoise.c"
    define HAVE_LINENOISE 1
    sqlite-add-shell-opt -DHAVE_LINENOISE=1
    return "linenoise"
  } elseif {[opt-bool editline]} {
    # --enable-editline. The problem is finding a system which has it
    # available to test on. The man pages for it on OpenBSD do not
    # match how shell.c uses it. OpenBSD has a lib named libedit but
    # no headers to go with it. The legacy configure script looked for
    # readline() in libedit (and libedit.a indeed has the
    # readline/history functions used by shell.c) but shell.c expects
    # to find <editline/readline.h> when HAVE_EDITLINE=1, and that
    # file is nowhere to be found.
    #
    # However, a workaround which works on the available systems is:
    #
    # --with-readline-ldflags=-ledit
    #
    # And then let it detect readline.h. We "could" re-map
    # --enable-editline to do exactly that but it seems likely to
    # break on systems for which which HAVE_EDITLINE=1 previously
    # worked.
    proj-indented-notice -error {
      ERROR: the --enable-editline flag is not supported due to
      non-availability of systems which have it in a form which the
      sqlite3 CLI shell expects to see. On some systems this can be
      worked around by passing --with-readline-ldflags=-ledit instead
      of --enable-editline, which will attempt to use the readline.h
      supplied by libreadline but link against -ledit. On systems
      tested so far, that works.
    }
    return "none"
  } elseif {![opt-bool readline]} {
    msg-result "Readline support explicitly disabled with --disable-readline"
    return "none"
  }

  # Transform with-readline-header=X to with-readline-cflags=-I...
  set v [opt-val with-readline-header]
  proj-opt-set with-readline-header ""
  if {"" ne $v} {
    if {"auto" eq $v} {
      proj-opt-set with-readline-cflags auto
    } else {
      set v [file dirname $v]
      if {[string match */*line $v]} {
        # Special case: if the path includes .../*line/readline.h", set
        # the -I to one dir up from that because our sources include
        # <readline/readline.h> or <editline/readline.h>.  Reminder: if
        # auto.def is being run by jimsh0 then [file normalize] will not
        # work!
        set v [file dirname $v]
      }
      proj-opt-set with-readline-cflags "-I$v"
    }
  }

  # Look for readline.h
  set rlInc [opt-val with-readline-cflags auto]
  if {"auto" eq $rlInc} {
    set rlInc ""
    if {!$::cross_compiling} {
      # ^^^ this check is derived from the legacy configure script
      set rlInc [proj-search-for-header-dir readline.h \
                 -dirs {/usr /usr/local /usr/local/readline /usr/contrib /mingw} \
                 -subdirs {include/readline include}]
      # ^^^ The -dirs and -subdirs lists are from the legacy configure script
      if {"" ne $rlInc} {
        if {[string match */*line $rlInc]} {
          # See notes above for --with-readline-header
          set rlInc [file dirname $rlInc]
        }
        set rlInc "-I${rlInc}"
      }
    }
  }

  # If readline.h was found/specified, look for libreadline...
  set rlLib ""
  if {"" ne $rlInc} {
    set rlLib [opt-val with-readline-ldflags]
    if {"" eq $rlLib || "auto" eq $rlLib} {
      set rlLib ""
      set libTerm ""
      if {[proj-check-function-in-lib tgetent {readline ncurses curses termcap}]} {
        # ^^^ that libs list comes from the legacy configure script ^^^
        set libTerm [get-define lib_tgetent]
        undefine lib_tgetent
      }
      if {"readline" eq $libTerm} {
        set rlLib $libTerm
      } elseif {[proj-check-function-in-lib readline readline $libTerm]} {
        set rlLib [get-define lib_readline]
        lappend rlLib $libTerm
        undefine lib_readline
      }
    }
  }

  if {"" ne $rlLib} {
    set rlLib [join $rlLib]
    set rlInc [join $rlInc]
    define LDFLAGS_READLINE $rlLib
    define CFLAGS_READLINE $rlInc
    define HAVE_READLINE 1
    sqlite-add-shell-opt -DHAVE_READLINE=1
    msg-result "Using readline flags: $rlInc $rlLib"

    # Now check whether rl_completion_matches() has a signature we can use.
    # cctest is producing unexpected test output when using:
    #   -includes {stdio.h readline/readline.h}
    # so we have to use -source instead and write the whole test app inline
    if {[cctest \
           -cflags $rlInc -libs $rlLib -nooutput 1 -source {
             #include <stdio.h>
             #include <readline/readline.h>
             static char * rcg(const char *z, int i){return 0;}
             int main(void) {
               char ** x = rl_completion_matches("one", rcg);
               return 0;
             }
           }]} {
    } else {
      user-notice "WARNING: readline completion disabled due to rl_completion_matches() signature mismatch"
      show-notices
      sqlite-add-shell-opt -DSQLITE_OMIT_READLINE_COMPLETION
    }

    # Now check whether rl_completion_matches() has a signature we can use.
    # cctest is producing unexpected test output when using:
    #   -includes {stdio.h readline/readline.h}
    # so we have to use -source instead and write the whole test app inline
    if {[cctest \
           -cflags $rlInc -libs $rlLib -nooutput 1 -source {
             #include <stdio.h>
             #include <readline/readline.h>
             static char * rcg(const char *z, int i){return 0;}
             int main(void) {
               char ** x = rl_completion_matches("one", rcg);
               return 0;
             }
           }]} {
      user-notice "Readline completion enabled"
    } else {
      user-notice "WARNING: readline completion disabled due to rl_completion_matches() signature mismatch"
      sqlite-add-shell-opt -DSQLITE_OMIT_READLINE_COMPLETION
    }
    return "readline"
  }

  return "none"
}; # sqlite-check-line-editing
msg-result "Line-editing support for the sqlite3 shell: [sqlite-check-line-editing]"

proj-if-opt-truthy load-extension {
  if {[proj-check-function-in-lib dlopen dl]} {
    define LDFLAGS_DLOPEN [get-define lib_dlopen]
    undefine lib_dlopen
  } else {
    user-error "dlopen() not found. Use --disable-load-extension to bypass this check."
  }
} {
  define LDFLAGS_DLOPEN ""
  sqlite-add-feature-flag {-DSQLITE_OMIT_LOAD_EXTENSION=1}
  msg-result "Disabling loadable extensions."
}

proj-if-opt-truthy math {
  if {![proj-check-function-in-lib ceil m]} {
    user-error "Cannot find libm functions. Use --disable-math to bypass this."
  }
  define LDFLAGS_MATH [get-define lib_ceil]
  undefine lib_ceil
  sqlite-add-feature-flag {-DSQLITE_ENABLE_MATH_FUNCTIONS}
  msg-result "Enabling math SQL functions [get-define LDFLAGS_MATH]"
} {
  define LDFLAGS_MATH ""
  msg-result "Disabling math SQL functions"
}

define cross_compiling ${cross_compiling}

########################################################################
# Emscripten SDK for building the web-based wasm components.
#
set emccsh $srcdir/tool/emcc.sh
if {![get-define HAVE_WASI_SDK] && [proj-check-emsdk]} {
  define EMCC_WRAPPER $emccsh
  proj-make-from-dot-in $emccsh
  catch {exec chmod u+x $emccsh}
} else {
  define EMCC_WRAPPER ""
  file delete -force $emccsh
}
unset emccsh

########################################################################
# ICU - International Components for Unicode
#
# Handles these flags:
#
#  --with-icu-ldflags=LDFLAGS
#  --with-icu-config[=/path/to/icu-config]
#  --enable-icu-collations
#
# If both icu-ldflags and icu-config are provided, they are
# cumulative. If neither are provided, icu-collations is not honored
# and a warning is emitted if it is provided.
#
# Design note: though we can automatically enable ICU if the
# icu-config binary is found, we specifically do not. ICU is always an
# opt-in feature.
proc sqlite-check-icu {} {
  define LDFLAGS_ICU [join [opt-val with-icu-ldflags ""]]
  # Flags sets seen in the wild for ICU:
  # - -licui18n -licuuc -licudata
  # - -licui18n -licuuc
  # - /usr/local/bin/icu-config --ldflags
  if {[proj-opt-was-provided with-icu-config]} {
    set bin [opt-val with-icu-config]
    if {"auto" eq $bin} {
      set bin [proj-first-bin-of \
                 [get-define prefix]/bin/icu-config \
                 /usr/local/bin/icu-config \
                 /usr/bin/icu-config]
      if {"" eq $bin} {
        proj-fatal "--with-icu-config=auto cannot find icu-config binary"
      }
    }
    if {[file-isexec $bin]} {
      set x [exec $bin --ldflags]
      if {"" eq $x} {
        proj-fatal "$bin --ldflags returned no data"
      }
      define-append LDFLAGS_ICU $x
    } else {
      proj-fatal "--with-icu-config=$bin does not refer to an executable"
    }
  }
  set flags [define LDFLAGS_ICU [string trim [get-define LDFLAGS_ICU]]]
  if {"" ne $flags} {
    sqlite-add-feature-flag -shell -DSQLITE_ENABLE_ICU
    msg-result "Enabling ICU support with libs: $flags"
    if {[opt-bool icu-collations]} {
      msg-result "Enabling ICU collations."
      sqlite-add-feature-flag -shell -DSQLITE_ENABLE_ICU_COLLATIONS
      # Recall that shell.c builds with sqlite3.c
    }
  } elseif {[opt-bool icu-collations]} {
    proj-warn "ignoring --enable-icu-collations because neither --with-icu-ldflags nor --with-icu-config provided any linker flags"
  } else {
    msg-result "ICU support is disabled."
  }
}; # sqlite-check-icu
sqlite-check-icu

########################################################################
# Check for log(3) in libm and die with an error if it is not
# found. $why should be the feature name which requires that function
# (it's used only in error messages). defines LDFLAGS_MATH to the
# required linker flags (which may be empty even if the math APIs are
# found, depending on the OS).
proc affirm-have-math {why} {
  if {![msg-quiet proj-check-function-in-lib log m]} {
    user-error "Missing math APIs for $why"
  }
  define LDFLAGS_MATH [get-define lib_log ""]
  undefine lib_log
}

########################################################################
# Handle various SQLITE_ENABLE_... feature flags.
msg-result "Feature flags..."
foreach {boolFlag featureFlag ifSetEvalThis} {
  all         {} {
    proj-opt-set fts4
    proj-opt-set fts5
    proj-opt-set geopoly
    proj-opt-set rtree
    proj-opt-set session
  }
  fts4         -DSQLITE_ENABLE_FTS4    {affirm-have-math fts4}
  fts5         -DSQLITE_ENABLE_FTS5    {affirm-have-math fts5}
  geopoly      -DSQLITE_ENABLE_GEOPOLY {proj-opt-set rtree}
  rtree        -DSQLITE_ENABLE_RTREE   {}
  session      {-DSQLITE_ENABLE_SESSION -DSQLITE_ENABLE_PREUPDATE_HOOK} {}
  update-limit -DSQLITE_ENABLE_UPDATE_DELETE_LIMIT {}
  memsys5      -DSQLITE_ENABLE_MEMSYS5 {}
  memsys3      {} {
    if {[opt-bool memsys5]} {
      proj-warn "not enabling memsys3 because memsys5 is enabled."
      expr 0
    } else {
      sqlite-add-feature-flag -DSQLITE_ENABLE_MEMSYS3
    }
  }
} {
  proj-if-opt-truthy $boolFlag {
    sqlite-add-feature-flag $featureFlag
    if {0 != [eval $ifSetEvalThis] && "all" ne $boolFlag} {
      msg-result "  + $boolFlag"
    }
  } {
    if {"all" ne $boolFlag} {
      msg-result "  - $boolFlag"
    }
  }
}

########################################################################
# Invert the above loop's logic for some explicit SQLITE_OMIT_...
# cases. If config option $boolFlag is set, [sqlite-add-feature-flag
# $featureFlag], where $featureFlag is intended to be
# -DSQLITE_OMIT_...
foreach {boolFlag featureFlag} {
  json        -DSQLITE_OMIT_JSON
} {
  if {[proj-opt-truthy $boolFlag]} {
    msg-result "  + $boolFlag"
  } else {
    sqlite-add-feature-flag $featureFlag
    msg-result "  - $boolFlag"
  }
}

#########################################################################
# Show the final feature flag sets:
set oFF [get-define OPT_FEATURE_FLAGS]
if {"" ne $oFF} {
  define OPT_FEATURE_FLAGS [lsort -unique $oFF]
  msg-result "Library feature flags: [get-define OPT_FEATURE_FLAGS]"
}
set oFF [get-define OPT_SHELL]
if {"" ne $oFF} {
  define OPT_SHELL [lsort -unique $oFF]
  msg-result "Shell options: [get-define OPT_SHELL]"
}
unset oFF

########################################################################
# Maybe extend JimTCL a bit. As of this writing (2024-09-27) it only
# needs (-DHAVE_REALPATH or -DHAVE__FULLPATH) and -DHAVE_DIRENT_H to
# be compatible with our code generators. It can, however, be slightly
# extended via easy-to-detect features, should we need them.
if {0 && "" ne [get-define CFLAGS_JIMSH]} {
  foreach jimFunc {opendir fsync isascii} {
    if {[cc-check-functions $jimFunc]} {
      define-append CFLAGS_JIMSH -DHAVE_[string toupper $jimFunc]
    }
  }
  #These are hard-coded into jimsh0.c, so we must not -D them:
  #foreach jimDef {HAVE_UNISTD_H HAVE_DIRENT_H} {
  #  if {[is-defined $jimDef]} {
  #    define-append CFLAGS_JIMSH -D$jimDef
  #  }
  #}
  define-append CFLAGS_JIMSH -DHAVE_LONG_LONG; # SQLite relies on long long, so we know it's available
}; # JimTCL

########################################################################
# Generate the output files.
#
# Potential TODO (unclear): in sqlite3.pc.in, do we need to include
# any CFLAGS_READLINE, CFLAGS_ZLIB, etc in its "Cflags:" section?
proj-make-from-dot-in -touch Makefile sqlite3.pc
if {0} {
  # Requires a hand-written sqlite_cfg.h.in...
  proj-make-from-dot-in sqlite_cfg.h
  # vs...
} else {
  # Requires no input template...
  make-config-header sqlite_cfg.h \
    -bare {SIZEOF_* HAVE_DECL_*} \
    -none {HAVE_CFLAG_* LDFLAGS_* SH_* SQLITE_AUTORECONFIG
      TARGET_* USE_GCOV TCL_*} \
    -auto {HAVE_* PACKAGE_*} \
    -none *
  proj-touch sqlite_cfg.h ; # help avoid frequent unnecessary @SQLITE_AUTORECONFIG@
}
#TODO proj-make-from-dot-in ext/wasm/GNUmakefile

if {"" ne $DUMP_DEFINES_JSON} {
  ########################################################################
  # Dump config-defines.json...
  # Demonstrate (mis?)handling of spaces in JSON-export array values:
  # define-append OPT_FOO.list {"-DFOO=bar baz" -DBAR="baz barre"}
  define OPT_FEATURE_FLAGS.list [get-define OPT_FEATURE_FLAGS]
  define OPT_SHELL.list [get-define OPT_SHELL]
  set dumpDefsOpt {
    -bare {SIZEOF_* HAVE_DECL_*}
    -none {HAVE_CFLAG_* LDFLAGS_* SH_* SQLITE_AUTORECONFIG TARGET_* USE_GCOV TCL_*}
    -array {*.list}
    -auto {OPT_* PACKAGE_* HAVE_*}
  }
  if {[opt-bool defines-json-include-lowercase]} {
    lappend dumpDefsOpt -none {lib_*} ; # remnants from proj-check-function-in-lib and friends
    lappend dumpDefsOpt -auto {[a-z]*}
  }
  lappend dumpDefsOpt -none *
  proj-dump-defs-json $DUMP_DEFINES_JSON {*}$dumpDefsOpt
  undefine OPT_FEATURE_FLAGS.list
  undefine OPT_SHELL.list
}

########################################################################
# Some build-dev/debug-only output
proj-if-opt-truthy dump-defines {
  msg-result "--dump-defines is creating $::DUMP_DEFINES_TXT"
  make-config-header $::DUMP_DEFINES_TXT \
    -bare {SQLITE_OS* SQLITE_DEBUG USE_*} \
    -str {BIN_* CC LD AR LDFLAG* OPT_*} \
    -auto {*}
  # achtung: ^^^^ whichever SQLITE_OS_foo flag which is set to 0 will
  # get _undefined_ here unless it's part of the -bare set.
  if {0} {
    foreach x [all-defines] {
      puts "\t$x"
    }
  }
}

msg-result [proj-bold "Source tree is configured! Run make to build it."]