Re-enable 'index-info' and add support for 'root-desc' in cgitrc

The 'index-info' option got lost when the layout was converted from
sidebar to old-fashioned header (noticed by Harley Laue, thanks!), and
this commit re-enables it.

But there is now also an alternative in the 'root-desc' option; where
'index-info' specifies a file to include, 'root-desc' specifies the text
literally. This might be nicer for the one-liner descriptions which these
options typically provides.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgit.c

@@ -19,6 +19,8 @@ void config_cb(const char *name, const char *value)
 {
 	if (!strcmp(name, "root-title"))
 		ctx.cfg.root_title = xstrdup(value);
+	else if (!strcmp(name, "root-desc"))
+		ctx.cfg.root_desc = xstrdup(value);
 	else if (!strcmp(name, "css"))
 		ctx.cfg.css = xstrdup(value);
 	else if (!strcmp(name, "logo"))
@@ -159,6 +161,7 @@ static void prepare_context(struct cgit_context *ctx)
 	ctx->cfg.renamelimit = -1;
 	ctx->cfg.robots = "index, nofollow";
 	ctx->cfg.root_title = "Git repository browser";
+	ctx->cfg.root_desc = "a fast webinterface for the git dscm";
 	ctx->cfg.script_name = CGIT_SCRIPT_NAME;
 	ctx->page.mimetype = "text/html";
 	ctx->page.charset = PAGE_ENCODING;

cgit.h

@@ -132,6 +132,7 @@ struct cgit_config {
 	char *repo_group;
 	char *robots;
 	char *root_title;
+	char *root_desc;
 	char *script_name;
 	char *virtual_root;
 	int cache_dynamic_ttl;

ui-shared.c

@@ -510,7 +510,10 @@ void cgit_print_pageheader(struct cgit_context *ctx)
 		html_txt(ctx->repo->desc);
 	} else {
 		html(">");
-		html_txt("a fast webinterface for the git dscm");
+		if (ctx->cfg.root_desc)
+			html_txt(ctx->cfg.root_desc);
+		else if (ctx->cfg.index_info)
+			html_include(ctx->cfg.index_info);
 	}
 	html("</td></tr></table>\n");