check to see if we need all Windows compiler macros in preprocessor

This page http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system

Seems to say all we need is _WIN32 as it's defined on all Windows systems. This would make __CYGWIN32__ and __MINGW32__ redundant. Check to see this is the case

@houtanb What's needed to close this ticket?

@JohannesPfeifer the patience to replace the above definitions in the code and the ability to test them on various versions of Windows.

For future reference, here is a more succinct article: http://stackoverflow.com/questions/5919996/how-to-detect-reliably-mac-os-x-ios-linux-windows-in-c-preprocessor

@JohannesPfeifer do you compile the preprocessor on MinGW? Cygwin?

@houtanb A long time ago I used Cygwin, but I haven't done that in ages. Do you need it?

No, was just wondering what I can get rid of. I just need to check this with @FerhatMihoubi before making changes and closing this ticket.

@JohannesPfeifer so you don't use MinGW either?

@houtanb I use it for the use_dll Option, but I don't compile the preprocessor.

I confirm that the __MINGW32__ macro is redundant, and should be replaced by _WIN32.

On the contrary, __CYGWIN32__ is not redundant: on Cygwin, the _WIN32 macro is not defined. This is because Cygwin is a POSIX platform, therefore quite similar to Unix.

closed via commit preprocessor@5e6b8f0a