Add missing limits.h include from ares_getaddrinfo.c (#267)

This files references INT_MAX, but does not include limits.h. This can
cause a build failure on some platforms. Include limits.h if we have it.

Fix-by: Dan Noé <dpn@google.com>

ares_getaddrinfo.c

@@ -48,6 +48,10 @@
 #endif
 #include <assert.h>
 
+#ifdef HAVE_LIMITS_H
+#include <limits.h>
+#endif
+
 #include "ares.h"
 #include "bitncmp.h"
 #include "ares_private.h"