i_alloc: shave another 60 bytes off
kn_open: shave off 30 bytes
process: Add loadav calculator.

Needs to be exposed nicely to userspace yet.

Also remove a dead FIXME in the process code
z80pack: remove facepalm
Makefile: put string constants from the startup into discard as well

This lets us undo the buffer hack in a bit
binman: Pack the _DISCARD section so it can be relocated and discarded

This means platforms need to adjust their crt0.s as per the following
z80pack commits
z80pack: Keep discard separate

We can now discard the _DISCARD segment - yay, another 1K
z80pack: link _DISCARD at 0xE000
kdata,start: undo the bufpool hack

The strings should now end up in _DISCARD without hackery
msx1: update to new discard
msx2: update to new _discard logic
nc100: update to new _discard
trs80: update to new _discard
pcw8256: update to new _discard
z80pack-lite: update to new _discard
pcw8256: note zero requirement
socz80: update to new _discard
binman: sanity check data area, fix end reporting
z80pack32: Prototyping work to support 32K + 32K fixed better

Initial test work to see what is needed to handle machines that have a 32K
chunk you can page and a fixed 32K chunk (MTX512, N8VEM v2, MicroBee etc)

Buildable prototype but needs work doing on the crt0.s/binman setup to cope
with binaries containing a big hole in the middle.
z80pack: fix silly unfixed comment from early 48K setup