Hopefully fix the earlier broken if [ -n $(HEADERS_BITS_SUBARCH) ]

test by adding quotes. From Steve Papacharalambous.

Makefile.in

@@ -75,9 +75,11 @@ headers: include/bits/uClibc_config.h
 	for i in $(HEADERS_BITS_ARCH) ; do \
 		$(LN) -fs ../../libc/sysdeps/linux/$(TARGET_ARCH)/bits/$$i .; \
 	done; \
-	for i in $(HEADERS_BITS_SUBARCH) ; do \
-		$(LN) -fs ../../libc/sysdeps/linux/$(TARGET_ARCH)/bits/$(TARGET_SUBARCH)/$$i .; \
-	done
+	if [ -n "$(HEADERS_BITS_SUBARCH)" ] ; then \
+		for i in $(HEADERS_BITS_SUBARCH) ; do \
+			$(LN) -fs ../../libc/sysdeps/linux/$(TARGET_ARCH)/bits/$(TARGET_SUBARCH)/$$i .; \
+		done; \
+	fi
 	$(Q)\
 	cd include/sys; \
 	set -e; \