ndisc6: use LIBS for libintl

Use LIBS instead of LDFLAGS for "-lintl", otherwise LDFLAGS gets
evaluated to the left of object files and fails to link statically
because of incorrect symbol resolution order. Fixes:
http://autobuild.buildroot.net/results/21b/21bf88c9dbaecc204598e60dd9c7392a85068dd6/

Also rename patch to new naming convention.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/ndisc6/ndisc6.mk

@@ -14,7 +14,7 @@ NDISC6_LICENSE_FILES = COPYING
 
 ifeq ($(BR2_NEEDS_GETTEXT_IF_LOCALE),y)
 NDISC6_DEPENDENCIES += gettext
-NDISC6_CONF_ENV += LDFLAGS="$(TARGET_LDFLAGS) -lintl"
+NDISC6_CONF_ENV += LIBS="-lintl"
 endif
 
 NDISC6_BIN_ += dnssort # perl script