xmem takes the trace output of my malloc with mal_trace(1) and plots
a dynamic picture of the heap.

This represents in a window a range of numbers from 0 to MAX, where MAX is
the width * height of the window.  It accepts pairs of numbers from stdin
and treats them as ranges to be filled -- the i'th row on the screen
(starting from top) represents the range of numbers from i to i + width -
1.  A blank line causes an XFlush(), otherwise normal X buffering is used.
It also XFlushes on EOF, or when the input range is greater than can be
shown, in which case it pauses and waits to be killed by externally
killing the window or interrupting the program.

Uses the X Toolkit which makes it easy to expand and change.
Accepts all the standard Xt options.

This was a quick & dirty hack.  Needs cleanup.

	- moraes@csri.toronto.edu
