Waf is written in Python and supports adding additional tools for building different kinds of source files, different platform targets, etc. For our Boom OpenSLES project we have a crude Orc tool which compiles .orc files into .s assembly files. This currently only supports the SSE platform and doesn't support runtime compiling using liborc.
The orc.py tool needs to be refactored into Waf's code style (eg, tabs, not spaces), use Node.read_file and Node.write_file for better cross-platform support, support more platform options, learn about O_NOINHERIT, and write examples in a sample project folder for testing purposes.
When done, create a patch by using git-format and submit an enhancement request to the Waf bug tracker on googlecode and post the resulting URL to this task.