libc/glibc: fix downloading addons

Do to glibc what we did to eglibc in #dff359adf15c.

Only (very) old versions of glibc have other external addons,
and they are no longer meaningful.

But for consistency, do the change nonetheless.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 #!/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