two variables:
TOOLCHAIN_MISSING -- set to "yes" on platforms for which there is
no working in-tree toolchain (hppa, ns32k, sh5, x86_64).
EXTERNAL_TOOLCHAIN -- if defined by the user, points to the root of
an external toolchain (e.g. /usr/local/gnu). This enables the cross-build
framework even for TOOLCHAIN_MISSING platforms.
If TOOLCHAIN_MISSING is set to "yes", MKGDB, MKBFD, and MKGCC are all
unconditionally set to "no", since the bits are not there to build.
If EXTERNAL_TOOLCHAIN is set, MKGCC is unconditionally set to "no",
since the external toolchain's compiler is not in-sync with the
in-tree compiler support components (e.g. libgcc).
* Set MACHINE_CPU much earlier in bsd.own.mk, so that more tests in
that file can use it.
case:
MKBFD If set to "no", disables building of libbfd, libiberty,
and all things that depend on them (binutils/gas/ld, gdb,
dbsym, mdsetimage).
MKGDB If set to "no", disables bulding of gdb.
MKGCC If set to "no", disables building of gcc and the
gcc-related libraries (libg2c, libgcc, libobjc, libstdc++).
These are useful for building platforms for which either of the following
situations are true:
(1) You have no userland from which to run toolchain2netbsd
in order to build the appropriate toolchain build framework.
(2) The platform which you are building requires a newer set
of tools than are currently in the tree (e.g. x86-64, ia64).
* Regen files with proper OS names and version numbers.
* Clean up toolchain2netbsd somewhat, to get it ready to be cross-host
compatible (more work to be done here, but it's getting closer).
* Add framework for gdbreplay and gdbserver, but hold off on enabling these
by default until low-nbsd.c is verified to work everywhere.
the target "native toolchain" if BOOTSTRAP_NEW_TOOLCHAIN is set.
This is important if you don't have any userland at all, and you're
trying to make one from which you can run toolchain2netbsd.