library/int64.m:
library/uint64.m:
Add num_zeros/1, num_ones/1, num_leading_zeros/1, num_trailing_zeros/1
and reverse_bits/1.
configure.ac:
runtime/mercury_conf.h.in:
Add a new configuration macro that is defined if C's long type
is 64-bit.
tests/hard_coded/Mmakefile:
tests/hard_coded/bit_twiddle_uint64.{m,exp}:
tests/hard_coded/bit_twiddle_int64.{m,exp}:
Add tests of the above.
