Use GNU make pattern rules to handle multiple file output from bison.

With a pattern rule, the recipe will only be executed once, even when
the rule has multiple targets. Using this to handle the output from
bison is included as an example in the GNU make manual.

This fixes the makefiles so that bison-generated header files will be
regenerated if they are deleted.

Makefile.in

@@ -254,10 +254,9 @@ lexor.o: lexor.cc parse.h
 
 parse.o: parse.cc
 
-# Build this in two steps to avoid parallel build issues (see pr3462585)
-parse.cc: $(srcdir)/parse.y
-	$(YACC) --verbose -t -p VL --defines=parse.h -o $@ $<
-parse.h: parse.cc
+# Use pattern rules to avoid parallel build issues (see pr3462585)
+parse%cc parse%h: $(srcdir)/parse%y
+	$(YACC) --verbose -t -p VL --defines=parse.h -o parse.cc $<
 
 syn-rules.cc: $(srcdir)/syn-rules.y
 	$(YACC) --verbose -t -p syn_ -o $@ $<

driver/Makefile.in

@@ -85,10 +85,9 @@ iverilog@EXEEXT@: $O
 cflexor.c: $(srcdir)/cflexor.lex
 	$(LEX) -s -t $< > $@
 
-# Build this in two steps to avoid parallel build issues (see pr3462585)
-cfparse.c: $(srcdir)/cfparse.y
-	$(YACC) --verbose -t -p cf -d -o $@ $<
-cfparse.h: cfparse.c
+# Use pattern rules to avoid parallel build issues (see pr3462585)
+cfparse%c cfparse%h: $(srcdir)/cfparse%y
+	$(YACC) --verbose -t -p cf -d -o cfparse.c $<
 
 %.o: %.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) @DEPENDENCY_FLAG@ -c $< -o $*.o

tgt-pcb/Makefile.in

@@ -88,9 +88,8 @@ fp_lex.o: fp_lex.cc fp.h
 fp_lex.cc: $(srcdir)/fp.lex
 	$(LEX) -s -ofp_lex.cc $(srcdir)/fp.lex
 
-fp.cc: $(srcdir)/fp.y
-	$(YACC) --verbose -t -p fp --defines=fp.h -o $@ $<
-fp.h: fp.cc
+fp%cc fp%h: $(srcdir)/fp%y
+	$(YACC) --verbose -t -p fp --defines=fp.h -o fp.cc $<
 
 ifeq (@WIN32@,yes)
   TGTLDFLAGS=-L.. -livl

vhdlpp/Makefile.in

@@ -115,10 +115,9 @@ parse.o: parse.cc
 lexor.cc: $(srcdir)/lexor.lex
 	$(LEX) -s -olexor.cc $(srcdir)/lexor.lex
 
-# Build this in two steps to avoid parallel build issues (see pr3462585)
-parse.cc: $(srcdir)/parse.y
-	$(YACC) --verbose -t --defines=parse.h -o $@ $<
-parse.h: parse.cc
+# Use pattern rules to avoid parallel build issues (see pr3462585)
+parse%cc parse%h: $(srcdir)/parse%y
+	$(YACC) --verbose -t --defines=parse.h -o parse.cc $<
 
 lexor_keyword.o: lexor_keyword.cc parse.h
 

vpi/Makefile.in

@@ -149,20 +149,18 @@ sdf_lexor.o: sdf_lexor.c sdf_parse.h
 sdf_lexor.c: $(srcdir)/sdf_lexor.lex
 	$(LEX) -t $< > $@
 
-# Build this in two steps to avoid parallel build issues (see pr3462585)
-sdf_parse.c: $(srcdir)/sdf_parse.y
-	$(YACC) --verbose -t -p sdf -d -o $@ $<
-sdf_parse.h: sdf_parse.c
+# Use pattern rules to avoid parallel build issues (see pr3462585)
+sdf_parse%c sdf_parse%h: $(srcdir)/sdf_parse%y
+	$(YACC) --verbose -t -p sdf -d -o sdf_parse.c $<
 
 table_mod_lexor.o: table_mod_lexor.c table_mod_parse.h
 
 table_mod_lexor.c: $(srcdir)/table_mod_lexor.lex
 	$(LEX) -t $< > $@
 
-# Build this in two steps to avoid parallel build issues (see pr3462585)
-table_mod_parse.c: $(srcdir)/table_mod_parse.y
-	$(YACC) --verbose -t -p tblmod -d -o $@ $<
-table_mod_parse.h: table_mod_parse.c
+# Use pattern rules to avoid parallel build issues (see pr3462585)
+table_mod_parse%c table_mod_parse%h: $(srcdir)/table_mod_parse%y
+	$(YACC) --verbose -t -p tblmod -d -o table_mod_parse.c $<
 
 v2005_math.vpi: $(V2005) libvpi.a
 	$(CC) @shared@ -o $@ $(V2005) -L. $(LDFLAGS) -lvpi $(VA_MATH_VPI_LDFLAGS)

vvp/Makefile.in

@@ -140,10 +140,9 @@ parse.o: parse.cc
 
 tables.o: tables.cc
 
-# Build this in two steps to avoid parallel build issues (see pr3462585)
-parse.cc: $(srcdir)/parse.y
-	$(YACC) --verbose -t --defines=parse.h -o $@ $<
-parse.h: parse.cc
+# Use pattern rules to avoid parallel build issues (see pr3462585)
+parse%cc parse%h: $(srcdir)/parse%y
+	$(YACC) --verbose -t --defines=parse.h -o parse.cc $<
 
 lexor.cc: $(srcdir)/lexor.lex
 	$(LEX) -s -olexor.cc $(srcdir)/lexor.lex