[llvm] [Flang] explicitly link the pthread library when building shared flang-rt. (PR #129956)

[Michael Kruse via llvm-commits]

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@@ -142,6 +142,8 @@ function (add_flangrt_library name)
   endif ()
   if (build_shared)
     add_library("${name_shared}" SHARED ${extra_args} ${ARG_ADDITIONAL_HEADERS} ${ARG_UNPARSED_ARGUMENTS})
+    find_package(Threads REQUIRED)
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Meinersbur wrote:

Can you move `find_package(Threads REQUIRED)` to flang-rt/CMakeLists.txt? That's where all the requirements are being collected.

https://github.com/llvm/llvm-project/pull/129956