Re: Failure building libpq v18.0 on old aarch64

Daniele Varrazzo <daniele(dot)varrazzo(at)gmail(dot)com> writes:
> libpq v18 fails to build on aarch64 on rather old Centos versions. The error is:

> pg_crc32c_armv8_choose.c: In function ‘pg_crc32c_armv8_available’:
> pg_crc32c_armv8_choose.c:58:32: error: ‘HWCAP_CRC32’ undeclared
> (first use in this function)
> 58 | return (getauxval(AT_HWCAP) & HWCAP_CRC32) != 0;
> | ^~~~~~~~~~~

> and is related to the change in aac831cafa6f3106dfcbd3298757801c299351fc.

Hm. So it seems we should do one or both of

(1) add #ifdef guards checking that HWCAP_CRC32/HWCAP2_CRC32 is
available;

(2) figure out what we need to do to #include that header you found.

(1) seems like a good idea in any case. Given that this is such an
old system, I'm not that excited about (2), but maybe it's worth
troubling over?

regards, tom lane