date_strftime.c: check precision
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55410 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
date_strftime.c: check precision
large precision to get rid of buffer overflow.
reported by Guido Vranken .
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55410 b2dd03c8-39d4-4d8f-98ff-823fe69b080e