[Bug libgomp/41418] Can't build libgomp without --enable-languages=fortran

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41418

--- Comment #24 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Thomas Schwinge <[email protected]>:

https://gcc.gnu.org/g:e5efa9eff99da897f0bbd69455d8f7856985b2db

commit r17-3286-ge5efa9eff99da897f0bbd69455d8f7856985b2db
Author: Thomas Schwinge <[email protected]>
Date:   Tue Jul 28 20:46:16 2026 +0200

    libgomp: Revise libgomp/Fortran support conditionals

    Subversion r152931 (Git commit 0046b1a727f73f0848733e28219069426b2dc218)
    "Fix libgomp without --enable-languages=fortran", and its follow-up
    Subversion r156232 (Git commit d0709b6aeec6b00e71011502fa311751fc138147)
    "configure.ac: Test for executability of GFORTRAN",
    Subversion r156264 (Git commit 2122aa973ed2c829caee5b010a60ad01922a3650)
    "configure.ac: Test for executability of _the first word_ of GFORTRAN"
    fixed the libgomp target library build in case that
    '--enable-languages=fortran' was not in effect: in that case, disable
    libgomp/Fortran support.

    These changes certainly do the right thing in GCC configurations where
    '$GFORTRAN' would be expected to be "just compiled" (built with the GCC
    top-level build system).  However, in case that it's "pre-installed"
(provided
    externally, as determined by the GCC top-level build system), these changes
    didn't work, and instead kept libgomp/Fortran support disabled, instead of
    enabling it.  "Pre-installed" 'GFORTRAN="x86_64-w64-mingw32-gfortran
[...]"' is
    not accepted by the current 'test -x [...]' check, for instance, as
discussed
    in "libgomp: Fix gfortran detection when program is found via PATH",
    <https://inbox.sourceware.org/[email protected]>
    <https://forge.sourceware.org/gcc/gcc/pulls/172>,
   
<https://inbox.sourceware.org/bmm.hj9f44xa6a.gcc.gcc-TEST.Peter0x44.172.1.0@forge-stage.sourceware.org>.

    That proposed "libgomp: Fix gfortran detection when program is found via
PATH"
    patch has the issue that it picks up the "gfortran [...] found via PATH"
also
    in the case when GCC is configured without '--enable-languages=fortran' in
    effect, and it then still builds and installs the libgomp/Fortran support
files
    in GCC configurations without Fortran support enabled.

    Instead of "libgomp: Fix gfortran detection when program is found via PATH"
as
    proposed, we may revise libgomp/Fortran support conditionals generally, and
    handle that in a conceptually simpler way: revert the three aforementioned
    commits (in other words: simply again assign 'FC="$GFORTRAN"' (like
    'libgfortran/configure.ac' also is doing), and conditionalize 'USE_FORTRAN'
on
    whether '--enable-languages=fortran' is in effect.  In other words: in case
    that '--enable-languages=fortran' is in effect, assume that the
    'GFORTRAN=[...]' passed to the libgomp build is functional -- no matter
where
    it's coming from: "just compiled" or "pre-installed".

            PR libgomp/41418
            libgomp/
            * configure.ac (FC): Revert ealier changes; just set to
'"$GFORTRAN"'.
            (USE_FORTRAN): Conditionalize on '--enable-languages=fortran' being
in
            effect.
            * configure: Regenerate.

    Reported-by: Peter Damianov <[email protected]>