Current nightly build e72597e.

pch.h redefines _WIN32:

#if defined(WIN32)
// so you don't have to define this yourself as the code seems to use it...
#undef _WIN32
#define _WIN32
#endif

_WIN32 is a reserved symbol and should never be changes. This breaks e.g. compilation of Intels threading building blocks because they expect it to be defined as a number.

See:
http://predef.sourceforge.net/preos.html
http://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier