Merge branch 'cw/help-over-network'

"git help -w $cmd" can show HTML version of documentation for
"git-$cmd" by setting help.htmlpath to somewhere other than the
default location where the build procedure installs them locally;
the variable can even point at a http:// URL.

* cw/help-over-network:
  Allow help.htmlpath to be a URL prefix
  Add config variable to set HTML path for git-help --web

builtin/help.c

@@ -34,6 +34,8 @@ enum help_format {
 	HELP_FORMAT_WEB
 };
 
+static const char *html_path;
+
 static int show_all = 0;
 static unsigned int colopts;
 static enum help_format help_format = HELP_FORMAT_NONE;
@@ -265,6 +267,12 @@ static int git_help_config(const char *var, const char *value, void *cb)
 		help_format = parse_help_format(value);
 		return 0;
 	}
+	if (!strcmp(var, "help.htmlpath")) {
+		if (!value)
+			return config_error_nonbool(var);
+		html_path = xstrdup(value);
+		return 0;
+	}
 	if (!strcmp(var, "man.viewer")) {
 		if (!value)
 			return config_error_nonbool(var);
@@ -387,12 +395,15 @@ static void show_info_page(const char *git_cmd)
 static void get_html_page_path(struct strbuf *page_path, const char *page)
 {
 	struct stat st;
-	const char *html_path = system_path(GIT_HTML_PATH);
+	if (!html_path)
+		html_path = system_path(GIT_HTML_PATH);
 
 	/* Check that we have a git documentation directory. */
-	if (stat(mkpath("%s/git.html", html_path), &st)
-	    || !S_ISREG(st.st_mode))
-		die(_("'%s': not a documentation directory."), html_path);
+	if (!strstr(html_path, "://")) {
+		if (stat(mkpath("%s/git.html", html_path), &st)
+		    || !S_ISREG(st.st_mode))
+			die("'%s': not a documentation directory.", html_path);
+	}
 
 	strbuf_init(page_path, 0);
 	strbuf_addf(page_path, "%s/%s.html", html_path, page);