[CMake] MinGW-w64/MSYS2 (or Cygwin) and NAG Fortran - how to combine?

[Brad King]

On 2/14/2018 3:16 AM, Arjen Markus wrote:
> The MinGW version of Cmake reports Windows for both variables

Great, that's expected.  Then Windows-NAG-Fortran would be the proper
module for flags for a compiler targeting a Windows environment.

> and the MSYS2 version reports MSYS.

If CMAKE_SYSTEM_NAME is "MSYS" then likely all the `CYGWIN-*`
modules should become `MSYS-*` modules.

-Brad