fix building ripper: parse.h and id.h doesn't need directory

r40275 breaks Unix build.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40277 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/ripper/depend

@@ -15,8 +15,8 @@ ripper.o: ripper.c id.c lex.c eventids1.c eventids2.c eventids2table.c \
 	$(hdrdir)/ruby/util.h \
 	$(top_srcdir)/node.h \
 	$(top_srcdir)/internal.h \
-	{$(VPATH)}parse.h \
-	{$(VPATH)}id.h \
+	parse.h \
+	id.h \
 	$(top_srcdir)/regenc.h \
 	$(top_srcdir)/vm_opts.h \
 	$(topdir)/probes.h