When clang was changed to -fcommon, perl's P_hash_{seed,state} variables

When clang was changed to -fcommon, perl's P_hash_{seed,state} variables
moved into BSS in the .o, with padding rules following the types -- they
are both char[].  Since P_hash_seed is (system-dependent) not a multiple of 8,
P_hash_state gets layed out misaligned, which sucks because the hash functions
demand 64-bit alignment for both variables.  There is the possibility of using
misalignment macros, but this is not cheap.  Could also use kernel-trap fault
repair, but the performance would really suck for something so crucial.
The correct fix would be for upstream to declare these types as uint64[],
we have requested that in https://github.com/Perl/perl5/issues/18555
In the meantime, carry a diff to roundup P_hash_seed to 64-bit alignment so that
P_hash_state will land aligned.
ok afresh1