Add target for modindex.html; a combined lib+mac module index.  Also
built with target "all".
diff --git a/Doc/html/Makefile b/Doc/html/Makefile
index e8cf017..1119576 100644
--- a/Doc/html/Makefile
+++ b/Doc/html/Makefile
@@ -38,7 +38,7 @@
 	$(TOPDIR)/perl/l2hinit.perl
 
 
-all:	$(INDEXFILES)
+all:	$(INDEXFILES) modindex.html
 
 .PHONY: api ext lib mac ref tut
 
@@ -51,6 +51,10 @@
 
 $(INDEXFILES): $(COMMONPERL) $(TOPDIR)/html/about.dat
 
+modindex.html: lib/lib.html mac/mac.html $(TOOLSDIR)/mkmodindex
+	$(TOOLSDIR)/mkmodindex --columns 5 --output modindex.html \
+		lib/modindex.html mac/modindex.html
+
 api/api.html:  $(PAPERDIR)/api.aux $(BUILDINDEX)
 	$(MKHTML) api $(L2HARGS)