diff --git a/ext/mbstring/libmbfl/config.h.w32 b/ext/mbstring/libmbfl/config.h.w32
index 72d7ef55141e1..bb76dfe8276de 100644
--- a/ext/mbstring/libmbfl/config.h.w32
+++ b/ext/mbstring/libmbfl/config.h.w32
@@ -1,4 +1,3 @@
-#define HAVE_MEMORY_H 1
 /* #undef HAVE_STRINGS_H */
 /* #undef HAVE_STRCASECMP */
 #define HAVE_STRICMP 1