grep: Always use locale.h

grep: Always use locale.h

The changes in the grep 2.5 configuration always leave out
HAVE_LOCALE_H - it has been removed from other files, but
not from everywhere.

This leads to a crash in certain configurations where the
size of int is not the size of pointer; this happens because
setlocale() is used while being undeclared.

[YOCTO #3959]

(From OE-Core rev: 4ca3a19c6fb93a6e85017f7ae465b5d2eba9463e)

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>