[U-Boot] [PATCH] tools/Makefile: Move _GNU_SOURCE to Makefile

[Simon Glass]

  On Tue, Jul 30, 2013 at 4:26 PM, York Sun <yorksun at freescale.com> wrote:

> Commit 669dfc2e adds libfdt_env.h to HOSTCPPFLAGS. It causes stdio.h
> to be included before _GNU_SOURCE is defined in C files. On some old hosts
> some prototypes are protected by #ifdef __USE_GNU, which is set when
> _GNU_SOURCE is defined.
>
> Signed-off-by: York Sun <yorksun at freescale.com>
>

Acked-by: Simon Glass <sjg at chromium.org>

This seems safe enough to me.