<stdint.h> should expose SIZE_MAX.

Change-Id: Id27222c24955c83f29ad953933cbdc48b6f1e900
diff --git a/libc/include/stdint.h b/libc/include/stdint.h
index c3e29dd..222ff1b 100644
--- a/libc/include/stdint.h
+++ b/libc/include/stdint.h
@@ -30,6 +30,7 @@
 
 #include <stddef.h>
 #include <sys/_types.h>
+#include <machine/limits.h> /* For SIZE_MAX. */
 
 #if !defined(__cplusplus) || defined(__STDC_LIMIT_MACROS)
 #  define __STDINT_LIMITS