https://bugs.gentoo.org/662816

--- a/regex/CMakeLists.txt
+++ b/regex/CMakeLists.txt
@@ -15,6 +15,8 @@
 
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include)
 
+INCLUDE(${MYSQL_CMAKE_SCRIPT_DIR}/compile_flags.cmake)
+
 MY_CHECK_C_COMPILER_FLAG("-Wstringop-truncation" HAVE_STRINGOP_TRUNCATION)
 IF(HAVE_STRINGOP_TRUNCATION)
   ADD_COMPILE_FLAGS(