add missing header

diff --git a/ext/mbstring/libmbfl/mbfl/mbfl_allocators.h b/ext/mbstring/libmbfl/mbfl/mbfl_allocators.h
index 38a3f817efafa6c4b89f2fe53645a0839996b743..08fc275d04c1e8ffcd1c693f9d5129067f6ff7cb 100644 (file)
--- a/ext/mbstring/libmbfl/mbfl/mbfl_allocators.h
+++ b/ext/mbstring/libmbfl/mbfl/mbfl_allocators.h
@@ -31,6 +31,7 @@
 #ifndef MBFL_ALLOCATORS_H
 #define MBFL_ALLOCATORS_H
 
+#include <stddef.h>
 #include "mbfl_defs.h"
 
 typedef struct _mbfl_allocators {