config: make "Build shared libraries" depend on KERNEL_SUPPORTS_SHARED_LIBS

Now that all kernels that support shared libraries select the correct config
option, we can change the dependency rules of SHARED_LIBS accordingly.

#!/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