www/libevhtp: update 1.2.9 -> 1.2.10 and assorted fixes

• Update PORTVERSION, GH_TAGNAME, and distinfo for 1.2.10
• include/onigposix.h in PLIST when EVHTP_DISABLE_REGEX is not selected
• include/evthr.h when option EVHTP_DISABLE_EVTHR is not selected
• Add patch to ensure symbol gets exported from evhtp.h
• Recreated patch files for portlint

PR: 204054
Submitted by: trasz (original patch, multiple changes from maintainer)
Approved by: Ricky Gallamore <ultima1252@gmail.com> (maintainer)