add dummy 'add2lib' target to Grammar/Makefile so non-GNU makes don't bail out

This closes patch:
http://sourceforge.net/patch/index.php?func=detailpatch&patch_id=101176&group_id=5470
diff --git a/Grammar/Makefile b/Grammar/Makefile
index fe9eaa8..a490284 100644
--- a/Grammar/Makefile
+++ b/Grammar/Makefile
@@ -6,6 +6,9 @@
 
 all:		install
 
+# This target is used by the master Makefile to add the objects to the library
+add2lib:
+
 install:	$(DESTH) $(DESTC)
 
 depend: