Merging CVS with conditionals

If you do

   cvs diff --ifdef=NEWFEATURE file.c

you will get a file with all differences merged, but depending on the preprocessor symbol NEWFEATURE (-D has a different meaning for CVS merge, you'll have to use the long form). So you'll get something like:

void f()
 /* common code */
#ifndef NEWFEATURE
 /* deleted code */
#else
 /* added code */
#endif
 /* more common code */
}

Is also cool if you want to wrap changes in if()-else, you just have to search and replace the preprocessor code. The only thing that I don't like is the fact that the test is negativ, I would prefer

#ifdef NEWFEATURE
  /* added code */
#else
  /* deleted code */
#endif

since I don't like negative tests with else branches. But maybe it's just me. And it only works if you use C/C++ or their pre-processor, obviously.