Log Message:
Update to 8.20 (jit not enabled, should perhaps become an option?):

Release 8.20 21-Oct-2011
------------------------

The main change in this release is the inclusion of Zoltan Herczeg's
just-in-time compiler support, which can be accessed by building PCRE with
--enable-jit. Large performance benefits can be had in many situations. 8.20
also fixes an unfortunate bug that was introduced in 8.13 as well as tidying up
a number of infelicities and differences from Perl.