pycdep speed up in svn

I ran pycdep on the latest firefox source code, only to find out that it took 11 hours to generate the prolog database *ouch*. Running the prolog queries then took only a few seconds *yay*. Some speed tweaks are needed in the python part of pycdep.

In svn already changes have been committed that result in a more than 5 times speed up, but more optimizations may be needed in the future.

Running pycdep on the firefox code also revealed some weird include file path specifications that need further investigation.

Edited to add: profiling proved to be tricky business... in one particular instance, e.g. running pycdep on the same program twice, the first time it cost 37 seconds, the second time only 11 seconds. Is this the effect of caching? cpu frequency scaling (pycdep uses 100% processor time while it's running, and I'm running on a laptop)? Something else? It certainly doesn't make meaningful profiling easier...