Add rule for dummy config.h

Author: nobu

common.mk

@@ -677,6 +677,8 @@ install-prereq: $(CLEAR_INSTALLED_LIST) yes-fake sudo-precheck PHONY
 clear-installed-list: PHONY
 	@> $(INSTALLED_LIST) set MAKE="$(MAKE)"
 
+noarch_config_h = tmp/include/noarch/ruby/config.h
+
 clean: clean-ext clean-enc clean-golf clean-docs clean-extout clean-modular-gc clean-local clean-platform clean-spec
 clean-local:: clean-runnable
 	$(Q)$(RM) $(ALLOBJS) $(LIBRUBY_A) $(LIBRUBY_SO) $(LIBRUBY) $(LIBRUBY_ALIASES)
@@ -685,6 +687,7 @@ clean-local:: clean-runnable
 	$(Q)$(RM) probes.h probes.$(OBJEXT) probes.stamp ruby-glommed.$(OBJEXT) ruby.imp ChangeLog $(STATIC_RUBY)$(EXEEXT)
 	$(Q)$(RM) GNUmakefile.old Makefile.old $(arch)-fake.rb bisect.sh $(ENC_TRANS_D) builtin_binary.rbbin
 	$(Q)$(RM) $(PRISM_BUILD_DIR)/.time $(PRISM_BUILD_DIR)/*/.time yjit_exit_locations.dump
+	$(Q)$(RM) $(noarch_config_h)
 	-$(Q)$(RMALL) dump_ast$(BUILD_EXEEXT)*
 	-$(Q)$(RMALL) target
 	-$(Q) $(RMDIR) enc/jis enc/trans enc $(COROUTINE_H:/Context.h=) coroutine target \
@@ -858,6 +861,12 @@ $(arch:noarch=ignore)-fake.rb: $(srcdir)/template/fake.rb.in $(tooldir)/generic_
 	    i=- srcdir="$(srcdir)" BASERUBY="$(BASERUBY)" \
 	    LIBPATHENV="$(LIBPATHENV)" PRELOADENV="$(PRELOADENV)" LIBRUBY_SO="$(LIBRUBY_SO)"
 
+# dummy file for generating sources; $(arch_hdrdir)/ruby/config.h with prereq.status.
+$(noarch_config_h):
+	$(ECHO) generating dummy config.h
+	$(Q) $(MAKEDIRS) $(@D)
+	$(Q) $(TOUCH) $@
+
 noarch-fake.rb: # prerequisite of yes-fake
 	$(Q) exit > $@