[NaCl SDK] Add include of stdint.h to netdb.h

uint32_t is used in the declaration of getnetbyaddr but
stdin.h was not directly included.

This will be needed once this change the newlib headers
lands: https://codereview.chromium.org/1163893003

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4198

Review URL: https://codereview.chromium.org/1167113002

Cr-Commit-Position: refs/heads/master@{#333601}

native_client_sdk/src/libraries/third_party/newlib-extras/netdb.h

@@ -60,6 +60,7 @@
 #include <sys/cdefs.h>
 #include <sys/types.h>
 #include <machine/ansi.h>
+#include <stdint.h>
 #include <stdio.h>
 
 #ifndef __socklen_t_defined