fixed uninitialized keystate

SGI/IRIX fixes:
 - unaligned access in little endian conversion (which was erroneously done)
 - detect endianess and set appropriate macro
 - detect if CRTSCTS is defined before trying to use it (it's a BSD flag)
 - but first detect if the POSIX CCTS_OFLOW is available (hint: it's not on IRIX)