Merge pull request #1851 from tmash06/add_include_limit_h

add including limits.h.

include/mruby.h

@@ -34,6 +34,7 @@ extern "C" {
 
 #include <stdint.h>
 #include <stddef.h>
+#include <limits.h>
 
 #include "mrbconf.h"
 #include "mruby/value.h"

src/dump.c

@@ -6,6 +6,7 @@
 
 #include <ctype.h>
 #include <string.h>
+#include <limits.h>
 #include "mruby/dump.h"
 #include "mruby/string.h"
 #include "mruby/irep.h"