posix: when the last process in a process group goes down, destroy the group rather than trying to dereference a NULL pointer.
posix: read() returns -1 and errno=EAGAIN now if the file is not immediately available to reading and O_NONBLOCK is set.
posix: don't set flflags on a new descriptor to include 'mode' in open(), as mode is not flags.
posix: ioctl and fcntl now write some more debug, and aren't as zealous in modifying flflags.
scripts: buildLibc.py needs to remove ttyname.o from Newlib now