...since
<https://github.com/llvm/llvm-project/commit/a921d2d2fb46b898794091e7410426c518a4f0cc>
"[Driver] Add -print-multiarch", which causes an issue when building
ExternalProject_python3 on macOS:
> checking build system type... x86_64-apple-darwin19.6.0
> checking host system type... x86_64-apple-darwin19.6.0
[...]
> checking for the platform triplet based on compiler characteristics... darwin
configure: error: internal configure error for the platform triplet, please file a bug report
> make[1]: *** [/Users/stephan/Software/lo/core/external/python3/ExternalProject_python3.mk:80: /Users/stephan/Software/lo/core/workdir/ExternalProject/python3/build] Error 1
as workdir/UnpackedTarball/python3/configure.ac computes PLATFORM_TRIPLET as
"darwin", and instead of computing MULTIARCH as empty (as `$CC
--print-multiarch` used to just print
> clang: error: unsupported option '--print-multiarch'
> clang: error: no input files
to stderr), it now computes it as e.g. "x86_64-apple-darwin19.6.0" (or whatever
-target is explicitly set to in $CC), so the check that they have equal values
if they are bot nonempty fails now when building against Clang 13 trunk. (This
is not yet an issue with any Apple Clang version, though.)
Until this is eventually fixed upstream at <https://github.com/python/cpython>,
just keep pretending that `clang --print-multiarch` would cause no stdout output
on macOS when determining MULTIARCH.
Change-Id: Ic1b27c6791b327d5709a9d61a6d675c3fa8989bf
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115219
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>