[Bug tree-optimization/88156] ftree-vrp elides sign condition on mingw

[xantares09 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88156

--- Comment #4 from xantares09 at hotmail dot com ---
I found this in stddef.h:

#ifndef __WCHAR_TYPE__
/* wchar_t is unsigned short for compatibility with MS runtime */
#define __WCHAR_TYPE__ unsigned short
#endif