zlib.c: check EOF
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41014 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
zlib.c: check EOF
(gzreader_gets): check EOF. [ruby-core:55220] [Bug #8467]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41014 b2dd03c8-39d4-4d8f-98ff-823fe69b080e