library/int.m:
Add a new function `div'. The idea is that `div' is the same
as `//', except that `div' will round toward minus infinity, whereas
`//' will round toward zero. `div' is more well-behaved, `//'
is more efficient.
Change the behaviour of `mod' so that it is remainder after `div'
rather than remainder after `//'. This makes it more well-behaved,
but less efficient.
Add a new function `rem', which is the new name for what `mod'
used to do (i.e. remainder after `//').
compiler/llds.m:
Add some comments about the `/' and `mod' llds operators.
(The `mod' llds operator should probably be renamed `rem',
but I haven't done that yet.)
compiler/code_util.m:
Recognize `int:rem', rather than `int:mod', as the llds `mod'
operator.
tests/hard_coded/division_test.m:
Add some test cases for `div', `mod', `//', and `rem' on
negative numbers.
