configure.in: Check mblen().
eval_intern.h (CharNext): Don't use mblen() is not available.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40442 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
configure.in: Check mblen().
eval_intern.h (CharNext): Don't use mblen() is not available.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40442 b2dd03c8-39d4-4d8f-98ff-823fe69b080e