Added make check MOD=module for extensions.
Added make check MOD=module for extensions.

jpflori/flint2,fredrik-johansson/flint2,dsroche/flint2,wbhart/flint2,dsroche/flint2,dsroche/flint2,fredrik-johansson/flint2,dsroche/flint2,jpflori/flint2,jpflori/flint2,jpflori/flint2,wbhart/flint2,fredrik-johansson/flint2,wbhart/flint2