diff --git a/openmp/runtime/src/CMakeLists.txt b/openmp/runtime/src/CMakeLists.txt
--- a/openmp/runtime/src/CMakeLists.txt
+++ b/openmp/runtime/src/CMakeLists.txt
@@ -216,6 +216,28 @@
     WORKING_DIRECTORY ${LIBOMP_LIBRARY_DIR}
   )
 endif()
+# Copy headers to clang build directory structure
+# so it can find & use them before install
+if (NOT OPENMP_STANDALONE_BUILD)
+  # Had to manually copy this since CLANG_VERSION may be empty
+  set(major "${LLVM_VERSION_MAJOR}")
+  set(minor "${LLVM_VERSION_MINOR}")
+  set(patch "${LLVM_VERSION_PATCH}")
+  set(output_dir ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${major}.${minor}.${patch}/include)
+  function(copy_header_to_output_dir src_dir file)
+    set(src ${src_dir}/${file})
+    set(dst ${output_dir}/${file})
+    add_custom_command(TARGET omp POST_BUILD
+      DEPENDS ${src}
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different ${src} ${dst}
+      COMMENT "Copying OpenMP header ${file}...")
+  endfunction(copy_header_to_output_dir)
+  copy_header_to_output_dir(${CMAKE_CURRENT_BINARY_DIR} omp.h)
+  if(LIBOMP_OMPT_SUPPORT)
+    copy_header_to_output_dir(${CMAKE_CURRENT_BINARY_DIR} omp-tools.h)
+  endif()
+endif()
+
 set(LIBOMP_INCLUDE_DIR ${CMAKE_CURRENT_BINARY_DIR} PARENT_SCOPE)
 
 # Create *.inc before compiling any sources