Re: git diff looping?

  system,  orig:   0.22s
  system, paolo:   0.22s
  system,   ".":   0.15s
  compat,  orig: 150.88s
  compat, paolo:   0.43s
  compat,   ".":   0.15s

Besides the exponential behavior on the original regex, it is still
about twice as slow as the system one.

The reason is that the glibc regex is a DFA-based matcher.  It is much 
slower on regexes with backreferences, but otherwise it is faster.

  1. Replace the builtin diff.java.xfuncname pattern with what Paolo
     suggested (though I haven't verified its correctness beyond a
     cursory look at the results).

I checked it a bit harder, but still it is not easy to check because of 
the false positives in the original regex.  I'm pretty sure it's correct 
  though; I find it even easier to read (though longer) than the 
original one.

     I haven't looked at how large or how portable the glibc
     implementation is.

Decently portable, but I don't think it's worth it.  Users that write 
regexes so complex should know of the exponential behavior, I think.

Paolo