file suffixes

[Malcolm Wallace]

I recall that at one point GHC came with "bundles", built in "ways",
like profiling, parallel, tickyticky, etc..  There was also some
filename-mangling scheme for distinguishing .hi interface and .o
object files from the different bundles.

My question is, what was that filename-mangling scheme?  I ask because
I'm about to do something similar for nhc98's "ways" (heap-profiling,
time-profiling, tracing, etc.), and some consistency here might
be useful.

Regards,
    Malcolm