Feature Request: Opt ouf of blosc_get_cpu_features

[milesgranger]

Hello there.

I'm trying to build on musllinux, and also had this issue on x86_64-apple-darwin when statically linking:

/usr/local/musl/bin/../lib/gcc/x86_64-unknown-linux-musl/11.2.0/../../../../x86_64-unknown-linux-musl/bin/ld: /tmp/rustc88VirH/libblosc2-d98c3a018c009f3b.rlib(shuffle.c.o): in function `bitunshuffle':
          shuffle.c:(.text+0x523): undefined reference to `__cpu_model'

full example from workflow: https://github.com/milesgranger/cramjam/actions/runs/8749803819/job/24012143129#step:10:361

---

It appears this is based off determining HAVE_CPU_FEAT_INTRIN here:

c-blosc2/blosc/shuffle.c

Line 57 in 7611351

#define HAVE_CPU_FEAT_INTRIN

Then will try to get cpu features here:

c-blosc2/blosc/shuffle.c

Line 96 in 7611351

#if defined(HAVE_CPU_FEAT_INTRIN)

---

Feature request

I've found if I add an additional logic to opt out, ex "OPT_OUT_CPU_FEAT" to get this function instead, then everything is happy again. But there is also a good chance I'm missing something here. :)

c-blosc2/blosc/shuffle.c

Line 290 in 7611351

static blosc_cpu_features blosc_get_cpu_features(void) {

[milesgranger]

The workflow originally linked is to cramjam, some python bindings to the Rust bindings (blosc2-rs)

There is maybe a more relevant representation of the issue, you can see I have builds for other environment types and the one added here is failing for musl: https://github.com/milesgranger/blosc2-rs/actions/runs/8804935253/job/24166419904?pr=10#step:5:173

Happy to try out any forks/branches if that's helpful, thank you. 👍

[FrancescAlted]

I'm not the one who contributed that part of the code, but I'll be happy to try your approach. I suggest you to send a PR, let it run in the CI Actions here and see how it goes. Thank you!

[milesgranger]

xref: #603 (comment)