Use more precise `-march` by default

[markasoftware]

Eg, the raspberry pi 5 has crypto extensions (I think), so should be set to at least armv8-a+crypto (this can affect building wolfssl in some scenarios). The full list of options is at https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html . I'm no raspi expert and definitely don't want to do the digging myself to figure out which extensions are supported on which generations.

---

Add a 👍 reaction to issues you find important.

[nvmd]

Hi!
Thank you for an idea for enhancement, I think that would be nice to provide this optimization in a tailored nixpkgs version as an opt-in. As a part of nixosSystemFull, for example.
The downside could be, though, that such a nixpkgs version will require potentially everything to be rebuilt.

In fact, I did some experiments some time ago, but I didn't succeed in getting those optimization options picked by build processes for all packages by default.

Maybe you could suggest which particular packages could be especially good candidates for applying such optimization options specifically to them?

[nvmd]

I've found the old experiment with optimized nixpkgs I've mentioned above. In case anyone wants to pick up the task, here is the gist to provide some inspiration: https://gist.github.com/nvmd/a544e8ec222094980e729505e55164e9