RTS options for hackers, debuggers, and over-interested souls

These RTS options might be used (a) to avoid a GHC bug, (b) to see "what's really happening", or (c) because you feel like it. Not recommended for everyday use!

`-B':

Sound the bell at the start of each (major) garbage collection. Oddly enough, people really do use this option! Our pal in Durham (England), Paul Callaghan, writes: "Some people here use it for a variety of purposes -- honestly! -- e.g., confirmation that the code/machine is doing something, infinite loop detection, gauging cost of recently added code. Certain people can even tell what stage [the program] is in by the beep pattern. But the major use is for annoying others in the same office..."

`-r<file>':

Produce "ticky-ticky" statistics at the end of the program run. The `<file>' business works just like on the `-S' RTS option (above). "Ticky-ticky" statistics are counts of various program actions (updates, enters, etc.) The program must have been compiled using `-fstg-reduction-counts' (a.k.a. "ticky-ticky profiling"), and, for it to be really useful, linked with suitable system libraries. Not a trivial undertaking: consult the installation guide on how to set things up for easy "ticky-ticky" profiling.

`-T<num>':

An RTS debugging flag; varying quantities of output depending on which bits are set in <num>.

`-Z':

Turn off "update-frame squeezing" at garbage-collection time. (There's no particularly good reason to turn it off.)