Tidy nacl_inttypes.h in preparation for making it work with nacl-glibc
Tidy nacl_inttypes.h in preparation for making it work with nacl-glibc

Add an #include guard.  Though there were apparently problems with
using an #include guard before, it seems to work OK now.

This means that the #undefs are not needed.

Change comment to clarify the newlib problem.

BUG=http://code.google.com/p/nativeclient/issues/detail?id=617
TEST=python build.py -sb libnacl_headers-input libnacl_headers libnacl_x86_32-input libnacl_x86_32

Review URL: http://codereview.chromium.org/3124043

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@3110 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client