How to extend XDG_DATA_DIRS?

[lukego]

I have a Lisp package that needs to add a directory to XDG_DATA_DIRS. What's the right way to do that?

(It's vk that needs to find vulkan-validation-layers for some data files loaded by the native libraries at runtime.)

[Uthar]

Hmm is usually I added such stuff in here

nix-cl/nix-cl.nix

Lines 294 to 300 in a66ff68

	--prefix CL_SOURCE_REGISTRY : "$CL_SOURCE_REGISTRY" \
	--prefix ASDF_OUTPUT_TRANSLATIONS : "$(echo $CL_SOURCE_REGISTRY | sed s,//:,::,g):" \
	--prefix LD_LIBRARY_PATH : "$LD_LIBRARY_PATH" \
	--prefix DYLD_LIBRARY_PATH : "$DYLD_LIBRARY_PATH" \
	--prefix CLASSPATH : "$CLASSPATH" \
	--prefix GI_TYPELIB_PATH : "$GI_TYPELIB_PATH" \
	--prefix PATH : "${makeBinPath (o.propagatedBuildInputs or [])}"