[clang] [openmp] [Libomp] Place generated OpenMP headers into build resource directory (PR #88007)

[Joseph Huber via cfe-commits]

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@@ -10,12 +10,19 @@
 
 include(ExtendPath)
 
+# The generated headers will be placed in clang's resource directory if present.
+if(${OPENMP_STANDALONE_BUILD})
+  set(LIBOMP_HEADERS_INTDIR ${CMAKE_CURRENT_BINARY_DIR})
+else()
+  set(LIBOMP_HEADERS_INTDIR ${LLVM_BINARY_DIR}/${LIBOMP_HEADERS_INSTALL_PATH})
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jhuber6 wrote:

LLVM is always built, I don't think it's possible to turn it off. Everything goes through `cmake ../llvm` so it will be set when that CMake runs.

https://github.com/llvm/llvm-project/pull/88007