Well, the summary says it all. . The first small steps were done quite some time ago, by rewriting every shell script that did not really need the shell in C or Smalltalk. Yesterday I finished the job, so that now it's possible to just do ../configure --host=i686-pc-mingw32 && make.

It took a while for two reasons: first because I overlooked wineconsole and it turns out it's a crucial step to running GNU Smalltalk under Wine; second, because GNU Smalltalk runs at build time, and it has to interact with the Unix paths.