This is a very simple memory leak detector using libexecinfo (in
OpenBSD ports as devel/libexecinfo). It could be adapted to use the
backtrace function in glibc too.

It tracks memory allocations by redirecting malloc/free and friends
to its own functions using preprocessor defines. When an allocation
is made, leakmalloc grabs the call chain from the stack and stores it.
When the program exits, leakmalloc dumps all unfreed allocations.

leakresolve.py consumes one of these dumps and produces a fairly
readable report with leaks coalesced by stack trace and sorted by
number of leak instances. Usually the last entry on this report is
the one to care most about.

leaky.c in regress/ shows how you might use it (run 'make' in that directory
and run it manually, or look at the Makefile for tips).

Note that everything needs to be compiled without optimisation and with
debugging symbols.