[Feature Request] PK3 symlink support

[Spike29]

Xonotic makes usage of in-PK3 symbolic link to deduplicate files in the distributed game, it’s a feature implemented in the Darkplaces engine.
For reference, here's the deduplicate script in question: https://gitlab.com/xonotic/xonotic/-/blob/master/misc/tools/symlink-deduplicate.sh?ref_type=heads

As such, there are also in-PK3 symlinks in our mapping support PK3: https://xonotic.org/download/#mappingsupport
NR supports them: https://netradiant.gitlab.io/post/2021-02-25-pk3-symlink/

In NRC, however, these symlinks aren't supported and appear as "shader image missing":

E.g. textures/effects_forcefield/forcefield1_c.jpg is actually a symlink to ../../models/xonotic_jumppad01/energy_yellow.jpg

Would it be possible to support these symbolic links? This feature would make the mapping experience for Xonotic more enjoyable with NRC.

(Alternatively, maybe we could also choose not to use symlinks in our mapping support PK3, but continue to use them in other distributed PK3s).

[Garux]

This hack imo adds more mess than value. Xonotic has legit mechanism to reuse image resources: shaders.

[Spike29]

Hmm, good point.
I don't know why we have duplicates in the first place, especially when both duplicates are in the textures folder, unlike in the example above where one of the duplicates is in the models folder.
On closer inspection, it seems that a cleaning up of our textures directory (and some shaders editing) wouldn't hurt. Maybe this feature request isn't needed once it's done.