Apply upstream fixes for a buffer overflow issue

1585 Fix buffer overflow for named references in (?| situations.

PR: 202209
Obtained from: PCRE svn (r1585)
Approved by: ports-secteam (feld), feld (mentor)
Security: ff0acfb4-3efa-11e5-93ad-002590263bf5
MFH: 2015Q3