diff --git a/cmake/sdlchecks.cmake b/cmake/sdlchecks.cmake
index 17d99b076..a09891cc7 100644
--- a/cmake/sdlchecks.cmake
+++ b/cmake/sdlchecks.cmake
@@ -817,8 +817,7 @@ endmacro()
 macro(CheckEGL)
   if (SDL_OPENGL OR SDL_OPENGLES)
     pkg_check_modules(EGL egl)
-    string(REPLACE "-D_THREAD_SAFE;" "-D_THREAD_SAFE=1;" EGL_CFLAGS "${EGL_CFLAGS}")
-    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${EGL_CFLAGS}")
+    set(CMAKE_REQUIRED_DEFINITIONS "${CMAKE_REQUIRED_DEFINITIONS} ${EGL_CFLAGS}")
     check_c_source_compiles("
         #define EGL_API_FB
         #define MESA_EGL_NO_X11_HEADERS