I've been searching and trying to fix it for Hours/Days now to finally find out it's a MinGW64 bug^^
basically I've got the same problem as the one in the link above since GCC 4.7 using http://sourceforge.net/projects/mingwbuilds/ or other sources (before that I used TDM-GCC 4.6.1 which works fine but is outdated)
__USE_MINGW_ANSI_STDIO is enabled by default even when I didn't want to (eg. didn't define it by myself) and as such printf macros like PRIu64 resolves to "llu" on Windows although it should be "I64u" and I'll get Compiler warnings about unknown conversion type character 'l' in format
I'm fine with using __USE_MINGW_ANSI_STDIO if it's faster then MSVCRT but not when it's not. Also I can't live with wrong compiler warnings as they happen here since they have to help me and not to do the opposite. (disabling them isn't an option since I'm not warned about real problems then as well)
Currently I'm unsure if it's a MinGW bug in general or just a GCC/porting bug...