As per the included README.Impt.License.Change, this advertising clause
does not need to be met and can be removed:
Accordingly, the foregoing paragraph of those BSD Unix files containing
it is hereby deleted in its entirety.
Signed-off-by: Damien George <damien@micropython.org>
Don't assume there's a POSIX system with read()/write(), etc., instead
accept function pointers to such routines via FILEVTABLE structure.
Other changes, like avoiding fstat() usage, using bundled version of BSD
sys/queue.h, etc.
