bn256 BN256_HAS_EXTINT required

[heifner]

crypto_primitives_tests/alt_bn128_pair_test fails if bn256 not compiled with BN256_HAS_EXTINT.

[spoonincode]

That's curious -- gcc, even 15.2, doesn't support _ExtInt/_BitInt in C++ mode. So there is plenty of CI coverage with BN256_HAS_EXTINT not set. Anything else unique about your environment? I noticed clang 20 gives a warning that warning: '_ExtInt' is deprecated; use '_BitInt' instead

[heifner]

Hmm. Must have been something else. I tried to reproduce the problem and have been unable to reproduce.