問題
$ ./configure ... checking if g++ supports template <class T> (required)... configure: WARNING: g++ template <class T> does not work checking if g++ supports GCC native atomic operations (optional)... no checking if g++ supports OSX native atomic operations (optional)... no checking if g++ environment provides all required features... no configure: error: Your compiler is not powerful enough to compile MeCab. If it should be, see config.log for more information of why it failed.
解決方法
$ sudo yum install gcc-c++
これで無事インストールできました。