Added a --global-module-index option to specify a (possibly relative) URL

to the Global Module Index for a set of documents.  This is used to include
a reference to the global index from the per-document module indexes, so
that it is just a little easier to find.

(Someone suggested this, but I do not remember who.  Please let me know if
it was you -- thanks!)

Doc/html/Makefile

@@ -14,7 +14,8 @@ PYTHON=	   python
 WEBCHECKER=$(PYTHON) $(TOPDIR)/../Tools/webchecker/webchecker.py
 MKHOWTO=   $(TOOLSDIR)/mkhowto --about $(TOPDIR)/html/stdabout.dat \
 		--address $(PYTHONDOCS) --up-link ../index.html \
-		--up-title "Python Documentation Index"
+		--up-title "Python Documentation Index" \
+		--global-module-index "../modindex.html"
 MKHTML=	   $(MKHOWTO) --html
 
 BUILDINDEX=$(TOOLSDIR)/buildindex.py

Doc/perl/l2hinit.perl

@@ -332,6 +332,16 @@ sub add_module_idx {
               . "<tt class='module'>$key</tt>$plat###\n";
     }
     close(MODIDXFILE);
+
+    if ($GLOBAL_MODULE_INDEX) {
+        $prefix = <<MODULE_INDEX_PREFIX;
+
+<p> This index only lists modules documented in this manual.
+  The <em class="citetitle"><a href="$GLOBAL_MODULE_INDEX">Global Module
+     Index</a></em> lists all modules that are documented in this set
+  of manuals.</p>
+MODULE_INDEX_PREFIX
+    }
     if (!$allthesame) {
 	$prefix .= <<PLAT_DISCUSS;
 

Doc/tools/mkhowto

@@ -91,6 +91,7 @@ class Options:
     quiet = 0
     runs = 0
     numeric = 0
+    global_module_index = None
     style_file = os.path.join(TOPDIR, "html", "style.css")
     about_file = os.path.join(TOPDIR, "html", "about.dat")
     up_link = None
@@ -117,7 +118,8 @@ class Options:
                                     "link=", "split=", "logging", "debugging",
                                     "keep", "quiet", "runs=", "image-type=",
                                     "about=", "numeric", "style=",
-                                    "up-link=", "up-title="]
+                                    "up-link=", "up-title=",
+                                    "global-module-index="]
                                    + list(self.ALL_FORMATS))
         for opt, arg in opts:
             if opt == "--all":
@@ -163,6 +165,8 @@ class Options:
                 self.up_link = arg
             elif opt == "--up-title":
                 self.up_title = arg
+            elif opt == "--global-module-index":
+                self.global_module_index = arg
             #
             # Format specifiers:
             #
@@ -405,6 +409,7 @@ class Job:
         l2hoption(fp, "MAX_SPLIT_DEPTH", options.max_split_depth)
         l2hoption(fp, "EXTERNAL_UP_LINK", options.up_link)
         l2hoption(fp, "EXTERNAL_UP_TITLE", options.up_title)
+        l2hoption(fp, "GLOBAL_MODULE_INDEX", options.global_module_index)
         fp.write("1;\n")
         fp.close()