[CMake] FindwxWidgets update (for MinGW)

[Werner Smekal]

Hi Miguel

> 
> If the wxWidgets instructions for MSYS recommend the configure/make
> process, then I'll just keep it simple and let MSYS build use the unix
> style search with the following change:
> 
> IF(WIN32 AND NOT CYGWIN AND NOT MSYS)
>   SET(wxWidgets_FIND_STYLE "win32")
> ELSE(WIN32 AND NOT CYGWIN AND NOT MSYS)
>   IF(UNIX OR MSYS)
>     SET(wxWidgets_FIND_STYLE "unix")
>   ENDIF(UNIX OR MSYS)
> ENDIF(WIN32 AND NOT CYGWIN AND NOT MSYS)

This should be correct.
> 
> However, as I understand it, you should not be installing too much
> into the msys system (certainly not something like wxWidgets) since it
> is meant to be a Minimal SYStem to aid the developers in using the
> bash shell, autotools, and a few other POSIX tools.

Since I wanted to make sure, here are some parts of the install.txt file 
of wxWidgets:

"NOTE: The makefile.gcc makefiles are for compilation under MinGW using
  Windows command interpreter (command.com/cmd.exe), they won't work in
  other environments (such as UNIX or Unix-like, e.g. MSYS where you have
  to use configure instead, see the section below)"

"6. The 'make install' step is optional, and copies files
    as follows:

    /usr/local/lib - wxmswXYZd.dll.a and wxmswXYZd.dll
    /usr/local/include/wx - wxWidgets header files
    /usr/local/bin - wx-config

    You may need to do this if using wx-config with the
    default root path."

I wouldn't use MSYS to compile wxWidgets anyway, since it's very slow 
compared to the CLI/MinGW combination. I don't think that many 
developers use that, but according to the installation instructions MSYS 
users must use configure and therefore we need the unix style find for 
this case.

Thanks for the bug fix!

Werner

-- 
Dr. Werner Smekal
Institut fuer Allgemeine Physik
Technische Universitaet Wien
Wiedner Hauptstr 8-10
A-1040 Wien
Austria

email: smekal at iap.tuwien.ac.at
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