Will Ultrix free() ever learn to reset brk() to free memory?

[rusty wright]

Notice that (on Ultrix 3.1 at least) the malloc man page says for
free:

	The argument to free is a pointer to a block previously
	allocated by malloc. This space is made available for further
	allocation, but its contents are left undisturbed.

I think it's historical and has something to do with the way malloc,
free, and realloc work/interact.  This is also what the man page says
for 4.3bsd, so I guess 4.3bsd isn't a "nice Unix system" either.