add bit arithmetic operations to eawk (implementation based on the gawk
man page). this provides:

and(x, y) (in C, x & y)
or(x, y) (in C, x | y)
xor(x, y) (in C, x ^ y)
lshift(x, n) (in C, x << n)
rshift(x, n) (in C, x >> n)
compl(x) (in C, ~x)

operations, with exactly the same calling conventions as gawk.

(agc)