"make tags": remove -t option of ctags

The option was kept for backward compatibility, but it was completly removed
recently. Patch written by Stéphane Wirtel.

Makefile.pre.in

@@ -1563,8 +1563,8 @@ autoconf:
 # Create a tags file for vi
 tags::
 	cd $(srcdir); \
-	ctags -w -t Include/*.h; \
-	for i in $(SRCDIRS); do ctags -w -t -a $$i/*.[ch]; \
+	ctags -w Include/*.h; \
+	for i in $(SRCDIRS); do ctags -w -a $$i/*.[ch]; \
 	done; \
 	sort -o tags tags