Constexpr attacks (pext only)
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 38400 W: 10057 L: 9749 D: 18594
Ptnml(0-2): 93, 4110, 10498, 4394, 105
https://tests.stockfishchess.org/tests/view/69d2073261a12cebe17edc04
compile time generation leads to sharing tables through the binary, resulting
in gain on fishtest, as well as reduced memory usage. The downside is slightly
longer compilation time.
Using pdep reduces table size 4x, and gains a little outside of fishtest as well.
closes https://github.com/official-stockfish/Stockfish/pull/6706
No functional change