Base Makefile improvements.

Instead of calling make in subdirectories using a sh for loop, use GNU
make's $(foreach ) to create a string of commands connected with &&.
This way an error in a subdirectory will stop the build, instead of
continuing on to the next subdirectory, which the old version does.

Also added rules to regenerate configure when configure.in changes,
and to run config.status --recheck when that happens.
(cherry picked from commit d098db0a06)

Makefile.in

@@ -72,7 +72,7 @@ PICFLAGS = @PICFLAG@
 LDFLAGS = @rdynamic@ @LDFLAGS@
 
 all: dep config.h _pli_types.h version.h ivl@EXEEXT@
-	for dir in $(SUBDIRS); do (cd $$dir ; $(MAKE) $@); done
+	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
 
 # In the windows world, the installer will need a dosify program to
 # dosify text files.
@@ -85,13 +85,13 @@ endif
 # This rule rules the compiler in the trivial hello.vl program to make
 # sure the basics were compiled properly.
 check: all
-	for dir in $(SUBDIRS); do (cd $$dir ; $(MAKE) check); done
+	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
 	test -r check.conf || cp $(srcdir)/check.conf .
 	driver/iverilog -B. -BPivlpp -tcheck -ocheck.vvp $(srcdir)/examples/hello.vl
 	vvp/vvp -M- -M./vpi ./check.vvp | grep 'Hello, World'
 
 clean:
-	for dir in $(SUBDIRS); do (cd $$dir ; $(MAKE) $@); done
+	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
 ifeq (@MINGW32@,no)
 	(cd driver-vpi ; $(MAKE) $@)
 endif
@@ -102,7 +102,7 @@ endif
 	rm -rf dep
 
 distclean: clean
-	for dir in $(SUBDIRS); do (cd $$dir ; $(MAKE) $@); done
+	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
 ifeq (@MINGW32@,no)
 	(cd driver-vpi ; $(MAKE) $@)
 endif
@@ -140,6 +140,11 @@ config.h: $(srcdir)/config.h.in
 _pli_types.h: $(srcdir)/_pli_types.h.in
 	./config.status --header=$@
 
+$(srcdir)/configure: $(srcdir)/configure.in
+	cd $(srcdir) && autoconf
+
+config.status: $(srcdir)/configure
+	./config.status --recheck
 
 ifeq (@WIN32@,yes)
 # Under Windows (mingw) I need to make the ivl.exe in two steps.
@@ -259,7 +264,7 @@ WIN32_INSTALL = $(bindir)/iverilog-vpi$(suffix)
 endif
 
 install: all installdirs $(libdir)/ivl$(suffix)/ivl@EXEEXT@  $(libdir)/ivl$(suffix)/include/constants.vams $(libdir)/ivl$(suffix)/include/disciplines.vams $(includedir)/ivl_target.h $(includedir)/_pli_types.h $(includedir)/vpi_user.h $(includedir)/acc_user.h $(includedir)/veriuser.h $(WIN32_INSTALL) $(INSTALL_DOC)
-	for dir in $(SUBDIRS); do (cd $$dir ; $(MAKE) $@); done
+	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
 
 $(bindir)/iverilog-vpi$(suffix): ./iverilog-vpi
 	$(INSTALL_SCRIPT) ./iverilog-vpi "$(DESTDIR)$(bindir)/iverilog-vpi$(suffix)"
@@ -304,7 +309,7 @@ installdirs: $(srcdir)/mkinstalldirs
 	    "$(DESTDIR)$(mandir)/man1"
 
 uninstall:
-	for dir in $(SUBDIRS); do (cd $$dir ; $(MAKE) $@); done
+	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
 	for f in ivl@EXEEXT@ include/constants.vams include/disciplines.vams; \
 	    do rm -f "$(DESTDIR)$(libdir)/ivl$(suffix)/$$f"; done
 	-rmdir "$(DESTDIR)$(libdir)/ivl$(suffix)/include"