bison - MSYS - Windows/DOS

[Gus Gassmann]

I am using bison 2.3 in MSYS. The setup works for me, but I have recently
become a bit more ambitious. What I would like to do is embed the bison command
into a Visual Studio build. The bison executable under MSYS is a Windows
executable, so this ought to work (it does work with flex), but I get an error
about not finding m4sugar.m4. Is there a command line option I could use to
override the default location?

Just to be perfectly clear:

bison -ldv -p osil -o OSParseosil.tab.cpp OSParseosil.y

works inside an MSYS box, but inside a DOS box gives me the error

bison: cannot open file `/usr/share/bison/m4sugar/m4sugar.m4': No such file or
directory

Is there a way that I can get this command to run in a DOS box?

Thanks