Lt advise

master commits:  open-mpi/ompi@f99e56d,  open-mpi/ompi@fe1aaa1.
master PRs: 
- https://github.com/open-mpi/ompi/pull/298
- https://github.com/open-mpi/ompi/pull/301

Note:
I aslo found that there is number of changes in macro naming:
ompi_show_subtitle -> opal_show_subtitle
OMPI_CHECK_WITHDIR -> OPAL_CHECK_WITHDIR
ompi_subdir_args   -> opal_subdir_args

So opal_setup_libltdl.m4 are still different .