Test with flang

[mathomp4]

We should test the GFE libraries with flang. For that we need flang. I was hoping I could be lazy and there would be a binary available, but as of LLVM 18.1.2, only selected arch/distro combos have that.

So, to source we go! My first attempt will be to build via the instructions here:

https://flang.llvm.org/docs/GettingStarted.html

I'll give it a go.

@tclune said that @everythingfunctional might have advice or know who might be a good contact if/when I have troubles, but hopefully all goes well 😄

[everythingfunctional]

I've generally had mixed results compiling flang. I do know that release 17.0.6 compiled and installed fine on Perlmutter, so if you have issues you may try that version specifically for debugging your process.

[mathomp4]

I've generally had mixed results compiling flang. I do know that release 17.0.6 compiled and installed fine on Perlmutter, so if you have issues you may try that version specifically for debugging your process.

@everythingfunctional Thanks! I'll probably go full bore bleeding edge first and see what breaks...then move back.