Python 2.7 will currently not compile with MinGW for the outlined reasons.

* There are several "#if defined(_MSC_VER)" macros which surround Windows specific code/preprocessor fragments. But _MSC_VER is only defined with the Visual Studio compiler, not with gcc/MinGW. So the MS_WINDOWS define needs to be used for Windows specific code (and _MSC_VER only for compiler specific code).

* When cross-compiling on Unix with gcc/MinGW, the windows.h header is only found if it's written all lowercase due to Unix filesystems being case-sensitive.

* strcasecmp is a already defined by gcc/MinGW, so it must not be used for defining another function. The patch thus renames a function currently named strcasecmp to my_strcasecmp.