[ARM] stdint.h should not rely on wchar_t being defined

[James Greenhalgh]

This patch to eglibc from debian (which is applied for Ubuntu 12.04):
  ( https://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=arm-eabi-wchar.patch;att=1;bug=444580 )

Gives this definition for __WCHAR_MAX in bits/wchar.h

#define __WCHAR_MAX ( (wchar_t) - 1 )

This then propagates to WCHAR_MAX from stdint.h:

# define WCHAR_MAX __WCHAR_MAX

The problem is that this introduces a requirement that stddef.h must be included before stdint.h in order to make the definition of wchar_t available.

In a conforming C implimentation, this should be valid:

#include "stdint.h"
#include "stdio.h"

unsigned int
foo (void)
{
  return (unsigned int) WCHAR_MAX;
}

Currently this will report:

gcc foo.c
foo.c: In function ‘foo’:
foo.c:7:25: error: ‘wchar_t’ undeclared (first use in this function)
foo.c:7:25: note: each undeclared identifier is reported only once for each function it appears in

The easiest fix would be to take the more modern, portable definition of WCHAR_MAX/__WCHAR_MAX from Ubuntu 14.04's glibc.

[James Greenhalgh (james-greenhalgh-y)]

This causes:

  FAIL: gcc.dg/c99-stdint-1.c (test for excess errors)
  FAIL: gcc.dg/c99-stdint-7.c (test for excess errors)

In the GCC testsuite, when testing a native arm-none-linux-gnueabihf toolchain under a Ubuntu 12.04 system.