ui-tree.c: add support for path-selected submodule links

The current 'repo.module-link' option is sufficient when all gitlinks
in a repository can be converted to commit links in a uniform way, but
not when different submodules/paths needs different settings.

This patch adds support for 'repo.module-link.<path>', which will be
used for linking to submodules at paths matching one such entry.

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

shared.c

@@ -71,6 +71,7 @@ struct cgit_repo *cgit_add_repo(const char *url)
 	ret->commit_filter = ctx.cfg.commit_filter;
 	ret->source_filter = ctx.cfg.source_filter;
 	ret->clone_url = ctx.cfg.clone_url;
+	ret->submodules.strdup_strings = 1;
 	return ret;
 }