exports.c: add blst_fp_from_{lb}e_bytes.

[dot-asm]

No description provided.

[jtraglia]

Typo in the title 😅

- blst_blst_from_{lb}e_bytes
+ blst_fp_from_{lb}e_bytes

[dot-asm]

Typo in the title 😅

Thanks!

[bellebaum]

This looks perfect :)
I actually prefer the generality here.

I don't know if you have any testing setup, but I did check some outputs of the big endian function against manual python-assisted calculations, and at least on my system I got what I expected given the code.

[dot-asm]

I've tested big-endian variant as replacement for the inner loop in hash_to_field and then compared results to be equal for few oversize random inputs for big- and little-endian variants, naturally with reversed bytes in the inputs.

[dot-asm]

Committed. Thanks.