Use ${HOST_SH} instead of the host system's /bin/sh wherever possible:

* Try to guess a suitable value for HOST_SH, if it was not set in
  the environment.  First try host-specific heuristics (Solaris has
  /usr/xpg4/bin/sh); then try to find the name of the shell that was used
  to run build.sh itself (by parsing the output from ps -p $$ -o comm);
  then fall back to "sh".

* Having found a value for HOST_SH, copy it to BSHELL and CONFIG_SHELL.

* Use ${HOST_SH} instead of /bin/sh when creating the make wrapper.

* Use ${HOST_SH} instead of unqualified sh when running shell scripts.

build.sh

@@ -1,5 +1,5 @@
 #! /usr/bin/env sh
-#	$NetBSD: build.sh,v 1.152 2006/09/01 21:52:55 uwe Exp $
+#	$NetBSD: build.sh,v 1.153 2006/09/29 19:53:54 apb Exp $
 #
 # Copyright (c) 2001-2005 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -38,12 +38,13 @@
 #
 # Top level build wrapper, for a system containing no tools.
 #
-# This script should run on any POSIX-compliant shell.  For systems
+# This script should run on any POSIX-compliant shell.  If the
-# with a strange /bin/sh, "ksh" or "bash" may be an ample alternative.
+# first "sh" found in the PATH is a POSIX-compliant shell, then
-#
+# you should not need to take any special action.  Otherwise, you
-# Note, however, that due to the way the interpreter is invoked above,
+# should set the environment variable HOST_SH to a POSIX-compliant
-# if a POSIX-compliant shell is the first in the PATH, you won't have
+# shell, and invoke build.sh with that shell.  (Depending on your
-# to take any further action.
+# system, one of /bin/ksh, /usr/local/bin/bash, or /usr/xpg4/bin/sh
+# might be a suitable shell.)
 #
 
 progname=${0##*/}
@@ -68,6 +69,83 @@ statusmsg()
 	${runcmd} echo "===> $@" | tee -a "${results}"
 }
 
+# Find a program in the PATH
+find_in_PATH()
+{
+	local prog="$1"
+	local oldIFS="${IFS}"
+	local dir
+	IFS=":"
+	for dir in ${PATH}; do
+		if [ -x "${dir}/${prog}" ]; then
+			prog="${dir}/${prog}"
+			break
+		fi
+	done
+	IFS="${oldIFS}"
+	echo "${prog}"
+}
+
+# Try to find a working POSIX shell, and set HOST_SH to refer to it.
+# Assumes that uname_s, uname_m, and PWD have been set.
+set_HOST_SH()
+{
+	# Even if ${HOST_SH} is already defined, we still do the
+	# sanity checks at the end.
+
+	# Solaris has /usr/xpg4/bin/sh.
+	#
+	[ -z "${HOST_SH}" ] && [ x"${uname_s}" = x"SunOS" ] && \
+		[ -x /usr/xpg4/bin/sh ] && HOST_SH="/usr/xpg4/bin/sh"
+
+	# Try to get the name of the shell that's running this script,
+	# by parsing the output from "ps".  We assume that, if the host
+	# system's ps command supports -o comm at all, it will do so
+	# in the usual way: a one-line header followed by a one-line
+	# result, possibly including trailing white space.  And if the
+	# host system's ps command doesn't support -o comm, we assume
+	# that we'll get an error message on stderr and nothing on
+	# stdout.  (We don't try to use ps -o 'comm=' to suppress the
+	# header line, because that is less widely supported.)
+	#
+	# If we get the wrong result here, the user can override it by
+	# specifying HOST_SH in the environment.
+	#
+	[ -z "${HOST_SH}" ] && HOST_SH="$(
+		(ps -p $$ -o comm | sed -ne '2s/[ \t]*$//p') 2>/dev/null )"
+
+	# If nothing above worked, use "sh".  We will later find the
+	# first directory in the PATH that has a "sh" program.
+	#
+	[ -z "${HOST_SH}" ] && HOST_SH="sh"
+
+	# If the result so far is not an absolute path, try to prepend
+	# PWD or search the PATH.
+	#
+	case "${HOST_SH}" in
+	/*)	:
+		;;
+	*/*)	HOST_SH="${PWD}/${HOST_SH}"
+		;;
+	*)	HOST_SH="$(find_in_PATH "${HOST_SH}")"
+		;;
+	esac
+
+	# If we don't have an absolute path by now, bomb.
+	#
+	case "${HOST_SH}" in
+	/*)	:
+		;;
+	*)	bomb "HOST_SH=\"${HOST_SH}\" is not an absolute path."
+		;;
+	esac
+
+	# If HOST_SH is not executable, bomb.
+	#
+	[ -x "${HOST_SH}" ] ||
+	    bomb "HOST_SH=\"${HOST_SH}\" is not executable."
+}
+
 initdefaults()
 {
 	cd "$(dirname $0)"
@@ -89,6 +167,15 @@ initdefaults()
 	unset PWD
 	TOP=$(/bin/pwd -P 2>/dev/null || /bin/pwd 2>/dev/null)
 
+	# The user can set HOST_SH in the environment, or we try to
+	# guess an appropriate value.  Then we set several other
+	# variables from HOST_SH.
+	#
+	set_HOST_SH
+	setmakeenv HOST_SH "${HOST_SH}"
+	setmakeenv BSHELL "${HOST_SH}"
+	setmakeenv CONFIG_SHELL "${HOST_SH}"
+
 	# Set defaults.
 	#
 	toolprefix=nb
@@ -711,9 +798,9 @@ rebuildmake()
 		${runcmd} cd "${tmpdir}"
 		${runcmd} env CC="${HOST_CC-cc}" CPPFLAGS="${HOST_CPPFLAGS}" \
 			CFLAGS="${HOST_CFLAGS--O}" LDFLAGS="${HOST_LDFLAGS}" \
-			sh "${TOP}/tools/make/configure" ||
+			${HOST_SH} "${TOP}/tools/make/configure" ||
 		    bomb "Configure of ${toolprefix}make failed"
-		${runcmd} sh buildmake.sh ||
+		${runcmd} ${HOST_SH} buildmake.sh ||
 		    bomb "Build of ${toolprefix}make failed"
 		make="${tmpdir}/${toolprefix}make"
 		${runcmd} cd "${TOP}"
@@ -819,7 +906,7 @@ validatemakeparams()
 	fi
 	if ${do_build} || ${do_distribution} || ${do_release}; then
 		if ! ${do_expertmode} && \
-		    [ $(id -u 2>/dev/null) -ne 0 ] && \
+		    [ "$(id -u 2>/dev/null)" -ne 0 ] && \
 		    [ "${MKUNPRIVED}" = "no" ] ; then
 			bomb "-U or -E must be set for build as an unprivileged user."
 		fi
@@ -879,9 +966,9 @@ createmakewrapper()
 	esac
 
 	eval cat <<EOF ${makewrapout}
-#! /bin/sh
+#! ${HOST_SH}
 # Set proper variables to allow easy "make" building of a NetBSD subtree.
-# Generated from:  \$NetBSD: build.sh,v 1.152 2006/09/01 21:52:55 uwe Exp $
+# Generated from:  \$NetBSD: build.sh,v 1.153 2006/09/29 19:53:54 apb Exp $
 # with these arguments: ${_args}
 #
 EOF
@@ -1030,6 +1117,8 @@ main()
 	statusmsg "${progname} command: $0 $@"
 	statusmsg "${progname} started: ${build_start}"
 
+	statusmsg "HOST_SH:          ${HOST_SH}"
+
 	rebuildmake
 	validatemakeparams
 	createmakewrapper