My understanding of both MSYS and MinGW, is they provide a minimal
system on which one can perform the usual "configure; make; make
install" sequence of commands. It is on this system that I build
Csound GBS for Windows.
I never create a Csound GBS distribution on MSYS as by default it does
not contain the autoreconf tool. Instead, I now create a distribution
on Fedora Core 4. If I had to create a distribution of Csound GBS on
Windows, I would install cygwin, as it is a non-minimal system that
includes everything one needs to build a distribution based that uses
a GNU Build System. Baring the above options, I would create a
distribution using a Live CD, such as KNOPPIX. Its got everything!