Assembly syntax incompatible with clang's internal assembler

[arnetheduck]

clang hashtree/src/sha256_avx_x8.S

hashtree/src/sha256_avx_x8.S:587:13: error: ambiguous operand size for instruction 'cmp'
        cmp NUM_BLKS, 0
            ^~~~~~~~
hashtree/src/sha256_avx_x8.S:615:6: error: ambiguous operand size for instruction 'cmp'
 cmp NUM_BLKS, 8
     ^~~~~~~~
...

Adding -no-integrated-as works around the problem by passing the file to the system as instead.

clang 17, b12467b

[potuz]

I don't think we'll ever switch to clang's internal assembler, so I'm closing this issue as running with the system assembler -no-integrated-as seems to work on all systems supported currently by the library. This was merged in #32 and workflow on linux was added in #34