It should be SYS_MBOX_EMPTY, not SYS_ARCH_TIMEOUT.
SYS_MBOX_EMPTY is defined to SYS_ARCH_TIMEOUT, so there is no bug.
But for good readability of the code, SYS_MBOX_EMPTY should be used.
This reverts commit a0d7b01186.
The new 'keypressed()' wasn't platform-independent but broke
the win32 port.
Signed-off-by: Simon Goldschmidt <goldsimon@gmx.de>