xitoa: fix internal _itoa
dosread: add the DOS tools.

These need SDCC 3.4.1 snapshots to build. At 25K it's also a bit tight on space
for a box with 32K binaries, but fine on a bigger setup
trs80: fix bogus static
utils; add pagesize
sysexits.h: BSD provides this and some BSDlike apps want to use it

Import directly.
utils: Make mkfs hopefully work and build a Fuzix fs
6809: remove dead timer reference
execve: fix build with CP/M emulator enabled
vt: add the framework for reporting the keyboard map and VT size
tty: add ioctl numbers for vt/kbd ops
dragon: vt/kbd ioctl support
msx2: add vt/kbd ioctls
mtx: add keyboard/vt ioctls
nc100: add vt/kbd ioctls
pcw8256: vt and kbd ioctls
trs80: kbd and vt ioctls
zx128: vt and kbd ioctls