I looked for existing answers first and saw that Valgrind is everyone’s favorite tool for memory leak debugging on linux. Unfortunately Valgrind does not seem
I would like to advertise my just announced heaptrack utility, which should be just what you where looking for back then. You can find more information here: http://milianw.de/blog/heaptrack-a-heap-memory-profiler-for-linux
Compared to your heapwatch tool, the performance should be far better, as I use libunwind and later libbacktrace to delay the annotation of the backtrace with DWARF debug information.
I'd love to get more feedback on it, so try it out!