samples/Mmakefile:
Add the beer program to list of targets.
samples/*.m:
Convert (C->T;E) to (if C then T else E).
Delete trailing whitespace.
Use predmode syntax instead of separate pred and mode
declarations.
samples/interpreter.m:
Fix up one predicate that had some clauses that used
DCGs and others that used state variables.
Don't use the name 'IO' for something that isn't the I/O state.
samples/diff/*.m:
samples/c_interface/c_calls_mercury/mercury_main.m:
samples/c_interface/short_example.m:
Delete trailing whitespace.
Estimatd hours taken: 0.5
Branches: main
samples/*.m:
Use '.' as the module qualifier instead of '__'.
Use the new foreign language interface.
Fix minor formatting issues.
Use state variables for passing the I/O state.
