Ok, I've done the following:
- disabled the maximum heap size by default. It can still be
enabled with +RTS -M<size>
- RTS options are taken from the GHCRTS environment variable
in addition to the command line (the command line has precedence).
- Compacting garbage collection is enabled when the residency
reaches a certain percentage of the maximum heap size (if there
is one).
Cheers,
Simon