Antony,
But unfortunately the Makefile.inc used to build hmake does some tricky $(PWD) shenanigans that have nothing to do with configure, and then passes the resulting path to ghc. Unfortunately, $(PWD) returns Cygwin-style paths, and I failed to find a good workaround for this in the few minutes I spent looking at it.
David Duke recently reported that the hmake distributed with nhc98-1.10 builds correctly with ghc-5.02.2 under Cygwin, but the separate distribution of hmake-3.01 does not. This was very puzzling, but your mention of $(PWD) rings a bell as to what the difference between them might be. The working distribution uses $(shell pwd) in its Makefiles instead of $(PWD). I recently changed all instances of the former to the latter because I couldn't see any reason why we should fork off lots of shell processes just to find the current directory, when that information is instantly available in a variable. It seems that the slight performance hit entailed by the shell calls is a necessary evil in order to cope with Cygwin, so I'll change them back again. Apologies for the inconvenience I have caused you by introducing this simple "improvement". It looked benign at the time! Regards, Malcolm