Make use of llvm-config if llvm include dir or llvm library is not found

cmake_modules/FindLibClang.cmake

@@ -115,6 +115,15 @@ find_library(LIBCLANG_LIBRARY NAMES libclang.imp libclang clang
     llvm18/lib llvm17/lib llvm16/lib llvm15/lib llvm140/lib llvm130/lib llvm120/lib llvm111/lib llvm110/lib llvm100/lib llvm90/lib llvm80/lib llvm71/lib llvm70/lib llvm60/lib llvm50/lib llvm41/lib llvm40/lib llvm39/lib llvm38/lib llvm37/lib llvm36/lib # FreeBSD
   DOC "The file that corresponds to the libclang library.")
 
+if (NOT LIBCLANG_INCLUDE_DIR)
+  execute_process(COMMAND /opt/homebrew/opt/llvm/bin/llvm-config --includedir OUTPUT_VARIABLE LIBCLANG_INCLUDE_DIR OUTPUT_STRIP_TRAILING_WHITESPACE)
+endif()
+
+if (NOT LIBCLANG_LIBRARY)
+  execute_process(COMMAND /opt/homebrew/opt/llvm/bin/llvm-config --libdir OUTPUT_VARIABLE LIBCLANG_LIBRARY_DIR OUTPUT_STRIP_TRAILING_WHITESPACE)
+  find_library(LIBCLANG_LIBRARY NAMES libclang.imp libclang clang PATHS $LIBCLANG_LIBRARY_DIR)
+endif()
+
 get_filename_component(LIBCLANG_LIBRARY_DIR ${LIBCLANG_LIBRARY} PATH)
 
 set(LIBCLANG_LIBRARIES ${LIBCLANG_LIBRARY})