Another patch from Olly Betts:
Another patch from Olly Betts:

This improves the shortcutting of backwards among - if there are fewer
characters available than the shortest string in the among, there's no way it
can match.  It also includes a cosmetic tweak (avoiding generating "z->c - 0"
in the output) which makes the generated source a little more readable (of
course the C compiler will optimise the "- 0" away anyway)


git-svn-id: 5f9301918bff60281e0250e0e7cf0b12b608e711@438 633ccae0-01f4-0310-8c99-d3591da6f01f

xjzhou/snowball,assem-ch/snowball,assem-ch/snowball,xjzhou/snowball,cesarsouza/snowball,snowballstem/snowball,cesarsouza/snowball,kariminf/snowball,snowballstem/snowball,JDemler/snowball,cesarsouza/snowball,assem-ch/snowball,omron93/snowball,assem-ch/snowball,omron93/snowball,goodotcom/snowball,goodotcom/snowball,kariminf/snowball,omron93/snowball,cesarsouza/snowball,JDemler/snowball,xjzhou/snowball,kariminf/snowball,snowballstem/snowball,cesarsouza/snowball,JDemler/snowball,xjzhou/snowball,snowballstem/snowball,xjzhou/snowball,kariminf/snowball,JDemler/snowball,snowballstem/snowball,goodotcom/snowball,assem-ch/snowball,JDemler/snowball,snowballstem/snowball,cesarsouza/snowball,goodotcom/snowball,snowballstem/snowball,kariminf/snowball,JDemler/snowball,snowballstem/snowball,cesarsouza/snowball