openmp issue on macmini

@chapman39 is already working on this.

Since Sep 18, 2025.

_from https://github.com/LLNL/serac/pull/1459 ..._

Openmp curiously is no longer able to be found during TPL builds. This may be related to Spack updates, but its more likely that I need to update `xcode` or something. Example of error when building `camp`:

```
1 error found in build log:
...
25 -- Creating BLT OpenMP targets...
>> 26 CMake Error at /Applications/CMake.app/Contents/share/cmake-3.23/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
27 Could NOT find OpenMP_C (missing: OpenMP_C_FLAGS OpenMP_C_LIB_NAMES)
...
```

After doing some investigating it seems the internet recommends `brew install libomp`. However, Spack doesn't really like that, given Spack randomly adds `-lgomp` to all TPLs:

` - tfpgb2s ^camp@2024.07.0 fflags=-fPIC ldflags=-L/opt/homebrew/opt/libomp/lib ldlibs='-lgomp' ...`

My guess as to why openmp could be found previously is that Spack found `gomp`, a GCC-openmp, located in `/opt/homebrew/lib/gcc/15`. But all the sudden it can't find it anymore(?). Alternatively, something internal to `xcode` was helping us find openmp..

I'll try updating my version of `xcode` on the macmini, but if that doesn't work we may need to reach out to some Spack people.