[llvm] [AIX] Add -pthread to build on AIX (PR #129108)

[David Tenty via llvm-commits]

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@@ -1182,6 +1182,7 @@ endif()
 if (UNIX AND ${CMAKE_SYSTEM_NAME} MATCHES "AIX")
           add_compile_definitions(_XOPEN_SOURCE=700)
           add_compile_definitions(_LARGE_FILE_API)
+          add_compile_options(-pthread)
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daltenty wrote:

note: We looked into this, it wasn't effective unfortunately

https://github.com/llvm/llvm-project/pull/129108