realloc

[Guy Harris]

 >Unfortunately, this is (at present) not a portable assumption, because
 >neither V6 nor V7 Unix -- the Unixes from which essentially all others
 >are descended, and which included the first widely-known C compilers -- 
 >did this.  It was invented later.  There are probably a fair number
 >of old systems that haven't caught up with it.

In fact, I checked the S5R3 "malloc"s - both the one in "libc", which
is, as I remember, little changed from the V7 one, and the one in
"-lmalloc" - and they most definitely do not make the check for NULL, so
there are probably a fair number of *new* systems that haven't caught up
with it.