cc/gcc: fix thread-less final gcc build

If threads are disabled in libc, we don't want to enable them in the
final compiler. Doing so pass the configure stage, but fails latter on
a missing <pthread.h>.

Moreover, we don't want to build libgomp if threads are disabled; its
configure script would fails anyway.

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>

 #!/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