Fix makefile rules for header files generated by bison.

bison 3.4.1 writes the header file before the c++ file. Our makefile
rules make the header files depend on the c++ files, so we need to
fix the timestamps accordingly.

Makefile.in

@@ -258,6 +258,7 @@ parse.cc: $(srcdir)/parse.y
 	$(YACC) --verbose -t -p VL -d -o $@ $<
 parse.h: parse.cc
 	mv parse.cc.h $@ 2>/dev/null || mv parse.hh $@
+	touch $@
 
 syn-rules.cc: $(srcdir)/syn-rules.y
 	$(YACC) --verbose -t -p syn_ -o $@ $<

tgt-pcb/Makefile.in

@@ -91,6 +91,7 @@ fp.cc: $(srcdir)/fp.y
 	$(YACC) --verbose -t -p fp -d -o $@ $<
 fp.h: fp.cc
 	mv fp.cc.h $@ 2>/dev/null || mv fp.hh $@
+	touch $@
 
 ifeq (@WIN32@,yes)
   TGTLDFLAGS=-L.. -livl

vhdlpp/Makefile.in

@@ -120,6 +120,7 @@ parse.cc: $(srcdir)/parse.y
 	$(YACC) --verbose -t -d -o $@ $<
 parse.h: parse.cc
 	mv parse.cc.h $@ 2>/dev/null || mv parse.hh $@
+	touch $@
 
 lexor_keyword.o: lexor_keyword.cc parse.h
 

vvp/Makefile.in

@@ -169,6 +169,7 @@ parse.cc: $(srcdir)/parse.y
 	$(YACC) --verbose -t -d -o $@ $<
 parse.h: parse.cc
 	mv parse.cc.h $@ 2>/dev/null || mv parse.hh $@
+	touch $@
 
 lexor.cc: $(srcdir)/lexor.lex
 	$(LEX) -s -olexor.cc $(srcdir)/lexor.lex