By telling cppcheck about the Microsoft Windows _countof() macro it is
now able to detect out of bounds array accesses like this:
wchar_t buf[10];
for(size_t i = 0; i <= (_countof(buf)); ++i) {
buf[i] = L'\0'; // (error) Array 'buf[10]' accessed at index 10, which
is out of bounds.
}