[compiler-rt] [llvm] Reapply "compiler-rt: Introduce runtime functions for emulated PAC." (PR #148094)

[Peter Collingbourne via llvm-commits]

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@@ -26,6 +26,7 @@ builtin_check_c_compiler_flag("-Xclang -mcode-object-version=none" COMPILER_RT_H
 builtin_check_c_compiler_flag(-Wbuiltin-declaration-mismatch COMPILER_RT_HAS_WBUILTIN_DECLARATION_MISMATCH_FLAG)
 builtin_check_c_compiler_flag(/Zl COMPILER_RT_HAS_ZL_FLAG)
 builtin_check_c_compiler_flag(-fcf-protection=full COMPILER_RT_HAS_FCF_PROTECTION_FLAG)
+builtin_check_c_compiler_flag(-nostdinc++          COMPILER_RT_HAS_NOSTDINCXX_FLAG)
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pcc wrote:

Yes, both `gcc` and `clang` (i.e. as opposed to `g++` and `clang++`) accept this flag.

https://github.com/llvm/llvm-project/pull/148094