I merged that patch into the grep trunk and am closing this bug report. 
  While merging, I removed one part of the patch that had a small but 
measurable performance degradation, namely, the introduction of struct 
dfatab.  I found some other minor simplifications and threw them in. 
There seems to be no significant change in CPU performance.  The patch's 
causes the dfa module's text size to shrink by 8% on my platform (x86-64 
Fedora 20), which I suppose is a small win, but the main point of the 
patch is simplifying the source.  I'm attaching what I installed, broken 
into 12 little patches to ease review.