[compiler-rt] [llvm] [LLVM][compiler-rt] Fix build with LLVM_USE_SANITIZER=Undefined (PR #120006)

[Dmitry Chestnykh via llvm-commits]

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@@ -1064,7 +1064,8 @@ if(LLVM_USE_SANITIZER)
   if (LLVM_USE_SANITIZE_COVERAGE)
     append("-fsanitize=fuzzer-no-link" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
   endif()
-  if (LLVM_USE_SANITIZER MATCHES ".*Undefined.*")
+  if (LLVM_USE_SANITIZER MATCHES ".*Undefined.*" AND CMAKE_C_COMPILER_ID MATCHES "Clang" AND
+		                                     CMAKE_CXX_COMPILER_ID MATCHES "Clang")
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chestnykh wrote:

Yes, but i don't touch `-fsanitize=undefined` argument, it passes both to clang and gcc. Here i disable `-fsanitize-blacklist=...` which doesn't supported by gcc

https://github.com/llvm/llvm-project/pull/120006