In the vast majority of cases, we can avoid temporary
allocations for paths in g_resources_enumerate_children().

In the case we need to add a suffix "/", we can usually just
build the path on the stack. In other cases, we can completely
avoid the strdup, which appears to only have been added for
readability. If the path is really long, we fallback to doing
what we did before, and use g_strconcat().

In the case of Builder, this saved 5.3mb of temporary
allocations in the process of showing the first application
window.

https://bugzilla.gnome.org/show_bug.cgi?id=790275