* If GCC is configured with `--disable-multi-arch`, `--print-multiarch` output is an empty line.
* If GCC is configured with `--enable-multi-arch`, `--print-multiarch` output may be a normalized triple or (on Debian, 'vendor' is omitted) `x86_64-linux-gnu`.
The Clang support D101400 just prints the Debian multiarch style triple
unconditionally, but the string is not really expected for non-Debian systems.
AIUI many Linux distributions and non-Linux OSes don't configure GCC with `--enable-multi-arch`.
Instead of getting us in the trouble of supporting all kinds of variants, drop the support as before D101400.
Close https://github.com/llvm/llvm-project/issues/51469
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D133170
This is useful in runtimes build for example which currently try to
guess the correct triple where to place libraries in the multiarch
layout. Using this flag, the build system can get the correct triple
directly by querying Clang.
Differential Revision: https://reviews.llvm.org/D101400
Fangrui Song