Bugs?
=====

ptr%=FNm_alloc(FNm_alloc(0))
----------------------------
If m_alloc(0) returns 0 because there is no memory available,
the outer m_alloc() is called as m_alloc(0) which will return
ptr% set to the amount of memory available. But we have already
been told there was no memory available, so ptr% will correctly
be zero.

Negative size
-------------
m_alloc(negative) cause problems, should return 0.

Scanning list
-------------
When scanning the slot list with UNTIL !A%>size% OR A%=0 at the end of
the list A% will be zero, but !A% will fetch from location zero which
is not part of the list.

Scan for match
--------------
Can't get scan for exact size to work.