Add patches to thunar from upstream bug report to mitigate crash
when renaming files.

The patch replaces some calls to strcmp() which are sometimes getting
NULL pointers, causing a crash, with safe calls to g_strcmp0()
calls, which handle NULL pointers gracefully.

I'm also adding a patch in another code path checking for a pointer
to actually point to the correct structure and not being NULL.

These patches seem to actually prevent the reported crash from
happening.

PR: 217946
Submitted by: Marko Cupac <marko.cupac@mimar.rs>
Obtained from: https://bugzilla.xfce.org/show_bug.cgi?id=12264