Fix assorted Makefile bugs

1. The target additional-maintainer-clean was misspelled as
maintainer-additional-clean.

2. Add add missing clean targets, in particular sysutils.o, config.h,
repmgr_version.h, and Makefile.global. While at it, use a wildcard
for obj files.

3. Don't delete configure.

4. Remove generated file doc/version.sgml from the repo.

5. Have maintainer-clean recurse to the doc directory.

Makefile.in

@@ -86,29 +86,15 @@ clean: additional-clean
 maintainer-clean: additional-maintainer-clean
 
 additional-clean:
-	rm -f repmgr-client.o
-	rm -f repmgr-action-primary.o
-	rm -f repmgr-action-standby.o
-	rm -f repmgr-action-witness.o
-	rm -f repmgr-action-bdr.o
-	rm -f repmgr-action-node.o
-	rm -f repmgr-action-cluster.o
-	rm -f repmgr-action-daemon.o
-	rm -f repmgrd.o
-	rm -f repmgrd-physical.o
-	rm -f repmgrd-bdr.o
-	rm -f compat.o
-	rm -f configfile.o
-	rm -f controldata.o
-	rm -f dbutils.o
-	rm -f dirutil.o
-	rm -f log.o
-	rm -f strutil.o
+	rm -f *.o
 
-maintainer-additional-clean: clean
-	rm -f configure
+additional-maintainer-clean: clean
+	$(MAKE) -C doc maintainer-clean
 	rm -f config.status config.log
+	rm -f config.h
+	rm -f repmgr_version.h
 	rm -f Makefile
+	rm -f Makefile.global
 	@rm -rf autom4te.cache/
 
 ifeq ($(MAJORVERSION),$(filter $(MAJORVERSION),9.3 9.4))

doc/Makefile.in

@@ -61,7 +61,7 @@ clean:
 
 maintainer-clean:
 	rm -rf html
-	rm -rf Makefile
+	rm -f Makefile
 
 zip: html
 	cp -r html repmgr-docs-$(REPMGR_VERSION)

doc/version.sgml

@@ -1 +0,0 @@
-<!ENTITY repmgrversion "4.3dev">