compiler/lco.m:
Fix the first bug, which was a compiler abort when lco tried to take
the address of a sub-word-sized argument. Don't allow this.
Don't allow the address to be taken of double-word arguments either,
until I can test whether this works.
Make a switch complete.
compiler/unify_gen.m:
Fix the second bug, which caused a compiler abort if we tried to take
the address of more than one field of a memory cell.
Factor out some common code.
tests/hard_coded/lco_pack_args_2.{m,exp}:
New test case for the first bug.
tests/hard_coded/lco_pack_args_3.{m,exp}:
New test case for the second bug.
tests/hard_coded/Mercury.options:
tests/hard_coded/Mmakefile:
Enable the new test cases.
