* Move the Cygwin/MSYS detection logic from config-*.mk into this new
script.
* Recognize either the 32-bit MinGW or the 32-bit MinGW-w64 compiler
driver for Cygwin.
My plan now is to integrate the PseudoConsole with Cygwin and MSYS ptys,
with initial focus on Cygwin. I think I'll keep the separate Agent and DLL
binaries, and they'll continue to be native Win32 binaries. I don't want
to have two build systems (qmake vs whatever MSYS/Cygwin uses), and since
I'd like to remove the Qt dependency anyway, I'm trying to switch to
makefiles.
