diff --git a/include/build_config/SDL_build_config.h.cmake b/include/build_config/SDL_build_config.h.cmake
index 3320b5cd53..63ea5f0bfe 100644
--- a/include/build_config/SDL_build_config.h.cmake
+++ b/include/build_config/SDL_build_config.h.cmake
@@ -49,7 +49,7 @@
 
 /* Comment this if you want to build without any C library requirements */
 #cmakedefine HAVE_LIBC 1
-#if HAVE_LIBC
+#ifdef HAVE_LIBC
 
 /* Useful headers */
 #cmakedefine HAVE_ALLOCA_H 1