Solved by myself - my first assumption was wrong:
Visual Studio 2012 uses SSE2 instructions by default. This causes trouble on old systems such as Intel Pentium III or AMD Athlon XP, which do not support SSE2. An invalid instruction exception is thrown.
You can switch of SSE2 using the /arch:IA32
compiler option.
The dynamically linked msvcrt (DLL) does work in all case, as it is not affected by the /arch
compiler option.