Currently, the experience of cen64 binaries of Windows is not the
greatest, to be kind. If you get the binary and double-click on it,
you get nothing (no feedback whatsoever). If you run it from the
console, you get nothing (no command line help is shown). I am not sure
how Windows users ever manage to use it.
This happens because the binary is linked as a windowed application,
but when run with no command line applications, it exits after printing
the help with printf, which does nothing since no console is
attached to the windowed application.
This PR improves the usability on Windows. It compiles cen64 has a
console application (as was meant to be used), so that the help text
or any other stdout/stderr output is now visible on console. Moreover,
to provide a decent experience to users double-clicking on the
binary, it displays an error message explaining that it should be run
from the command line instead.
