util-linux: fix libblkid detection

We don't have libblkid in BR, so make sure the configure script doesn't
detect it if it is installed on the host.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/util-linux/util-linux.mk

@@ -30,6 +30,7 @@ $(UTIL-LINUX_DIR)/.configured: $(UTIL-LINUX_DIR)/.unpacked
 	(cd $(UTIL-LINUX_DIR); rm -rf config.cache; \
 		$(TARGET_CONFIGURE_OPTS) \
 		$(TARGET_CONFIGURE_ARGS) \
+		ac_cv_lib_blkid_blkid_known_fstype=no \
 		./configure \
 		--target=$(GNU_TARGET_NAME) \
 		--host=$(GNU_TARGET_NAME) \