openmp_static.patch

diff --git a/faiss/CMakeLists.txt b/faiss/CMakeLists.txt
index 16eb9e9c..230adee2 100644
--- a/faiss/CMakeLists.txt
+++ b/faiss/CMakeLists.txt
@@ -251,8 +251,30 @@ target_compile_definitions(faiss PRIVATE FINTEGER=int)
 target_compile_definitions(faiss_avx2 PRIVATE FINTEGER=int)
 
 find_package(OpenMP REQUIRED)
-target_link_libraries(faiss PRIVATE OpenMP::OpenMP_CXX)
-target_link_libraries(faiss_avx2 PRIVATE OpenMP::OpenMP_CXX)
+
+# PATCH: statically link OpenMP into vss0 (for MacOS only)
+# On Macs, OpenMP_CXX_LIBRARIES always ends in .dylib for some reason,
+# to target_link_libraries will dynamically link openmp. This isn't ideal
+# for pre-compiled SQLite extensions, since users will have to 
+# "brew install libomp", which doesn't always work. So this patch is included
+# in MacOS builds for easier installations
+
+# same as OpenMP_CXX_LIBRARIES but with ".a" instead of ".dylib"
+set(_OPENMP_ARCHIVE_PATH "${OpenMP_CXX_LIBRARIES}")
+string(REPLACE ".dylib" ".a" _OPENMP_ARCHIVE_PATH ${_OPENMP_ARCHIVE_PATH})
+message("_OPENMP_ARCHIVE_PATH: ${_OPENMP_ARCHIVE_PATH}")
+
+# link to that .a file
+target_link_libraries(faiss PRIVATE ${_OPENMP_ARCHIVE_PATH})
+target_link_libraries(faiss_avx2 PRIVATE ${_OPENMP_ARCHIVE_PATH})
+
+# include openmp headers as well
+target_include_directories(faiss PUBLIC ${OpenMP_CXX_INCLUDE_DIRS})
+target_include_directories(faiss_avx2 PUBLIC ${OpenMP_CXX_INCLUDE_DIRS})
+
+# The original linking configurations
+#target_link_libraries(faiss PRIVATE OpenMP::OpenMP_CXX)
+#target_link_libraries(faiss_avx2 PRIVATE OpenMP::OpenMP_CXX)
 
 find_package(MKL)
 if(MKL_FOUND)