As the title say, that’s an error message which I received when trying to compile a php version with mm as a ./configure option.

fixing it is as easy as checking debug.log in your php source directory, searching where the php is looking for libraries (mine was in /usr/local/lib64) and than just creating a symlink for libmm.so.14 to /usr/local/lib64

Don’t have libmm at all? Go to http://www.ossp.org/pkg/lib/mm/ and install the library.

Update: apparently in php.ini you need to uncomment the session save path directive as otherwise the default path is / which triggers a permission error. Because of this the mm session handler does not get registered with php