-Wgcc-install-dir-libstdcxx is broken

[combinatorylogic]

Warnings about multiple gcc installations are issued even if clang driver got nothing to do with any gcc whatsoever (e.g., in combination with -stdlib=libc++ --rtlib=compiler-rt --unwindlib=libunwind). With -Wall -Werror it's very disruptive.

Observed on version: 22.1.2

[llvmorg-github-actions]

@llvm/issue-subscribers-clang-driver

Author: combinatorylogic

Details

Warnings about multiple gcc installations are issued even if clang driver got nothing to do with any gcc whatsoever (e.g., in combination with `-stdlib=libc++ --rtlib=compiler-rt --unwindlib=libunwind`). With -Wall -Werror it's very disruptive.

Observed on version: 22.1.2