cc: add a flag for skipping core passes

It is used for skipping unnecessary compilation steps when the libc
doesn't need to be compiled (eg. when we do not use a C library).

Signed-off-by: Yann Diorcet <diorcet.yann@gmail.com>
Message-Id: <150eadb0117e697d79aa.1353625025@blackmint>
Patchwork-Id: 201222

 #!/bin/sh

 # Needed for systems without gettext

 $* -xc -o /dev/null - > /dev/null 2>&1 << EOF

 #include <libintl.h>

 int main()

 {

 	gettext("");

 	return 0;

 }

 EOF

 if [ ! "$?" -eq "0"  ]; then

 	echo -DKBUILD_NO_NLS;

 fi