common.mk: partial revert r36867

* common.mk: revert r36867 partially, to use files in the source
  directory when out-of-place build.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36909 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

common.mk

@@ -560,8 +560,8 @@ $(ENC_MK): $(srcdir)/enc/make_encmake.rb $(srcdir)/enc/Makefile.in $(srcdir)/enc
 
 PHONY:
 
-parse.c: {$(VPATH)}parse.y $(srcdir)/tool/ytab.sed {$(VPATH)}id.h
-parse.h: {$(VPATH)}parse.c
+{$(VPATH)}parse.c: {$(VPATH)}parse.y $(srcdir)/tool/ytab.sed {$(VPATH)}id.h
+{$(VPATH)}parse.h: {$(VPATH)}parse.c
 
 {$(srcdir)}.y.c:
 	$(ECHO) generating $@