[cmake] Fix some macOS compilation errors (#4350)

Don't compile GLSL/GLASM backends without OpenGL enabled. These codepaths are unused on non-OpenGL platforms.

Fixes other miscellaneous errors that pop up on Clang 23 as well.

Signed-off-by: Lizzie lizzie@eden-emu.dev
Signed-off-by: crueter crueter@eden-emu.dev

- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------

Co-authored-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4350
Reviewed-by: crueter <crueter@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

tools/cpm/cmake/package/version.cmake

@@ -65,7 +65,7 @@ else()
 endif()
 
 # update cached cpmfile content
-string(JSON cpmfile SET "${cpmfile}" "${key}" "${new_object}")
+string(JSON cpmfile SET "${cpmfile}" "${KEY}" "${new_object}")
 
 # write cached cpmfile
 get_cpmfile_path(file)