[CMake] MinGW Compilers on Windows

[Kevan Hashemi]

Dear Alan,

> If you need/prefer Unix tools provided by MSYS to build your software,
> another possible generator you should look at is "MSYS Makefiles".

Thank you for this suggestion.

The CMake configuration and generation of OpenCV completes without errors using "MinGW Makefiles". I 
get one warning:

CMake Warning at cmake/OpenCVPackaging.cmake:23 (message):
CPACK_PACKAGE_VERSION does not match version provided by version.hpp header!

I assume that's a minor OpenCV-related error. When I "make", however, I enter some alternate shell 
program with a Microsoft copyright at the top. I suspect this is because I have sh.exe in my MSYS 
path, having seen this mentioned along the way, but if I remove sh.exe from the MSYS path, MSYS 
won't even execute "ls", so I'm not sure how to fix that problem, nor do I understand why it is a 
problem.

When I use "MSYS Makile", on the other hand, the OpenCV configuration and generation completes 
without warnings. When I "make", off it goes, compiling. After editing MinGW's commctrl.h file to 
solve an error related to OpenCV, the make completes and I have OpenCV built completely, which is 
really cool. I looked through the Makefile and it is awesome.

I'm curious as to why the "make" for the MinGW generator does not work. But I have a working build 
procedure, so I'm all set.

Yours, Kevan

-- 
Kevan Hashemi, Electrical Engineer
Physics Department, Brandeis University
http://alignment.hep.brandeis.edu/