Unix command environment for README.win32?

Ruby
1

The build instructions at
http://svn.ruby-lang.org/repos/ruby/trunk/win32/README.win32 require the
UNIX commands nmake, cl, lib, dumpbin, bison, sed, and ruby 1.8 or later
on Windows. What are the build scripts made to run with? MinGW or
Cygwin perhaps?

Thanks,
rcs