Log Message:
oniguruma: updated to 6.9.5.1

Release 6.9.5 revised 1
Fixed Issue 192

Release 6.9.5
(Same as Release Candidate 2)
POSIX API disabled by default for Unix (* Enabled by: configure \ 
--enable-posix-api=yes)
Update Unicode version 13.0.0
NEW: Code point sequence notation \x{HHHH HHHH ...}, \o{OOOO OOOO ...}
NEW API: retry limit in search functions
NEW API: maximum nesting level of subexp call
Fixed behavior of isolated options in Perl and Java syntaxes. /...(?i).../