Also include two other minor changes:
1. More C99-style member initialization in the component struct
1. Fix the BTL module member initialization to not be redundant
Add the functions that changed between BTL 2.0 and 3.0 into compat.h
and compat.c:
* module.btl_prepare_src: the signature and body of this method
changed between 2.0 and 3.0. However, the functions that this
method calls did *not* need to change, so they are copied over
wholesale (with the exception that they no longer accept the unused
`registration` parameter).
* module.btl_prepare_dst: this method does not exist in BTL 3.0.
* module.btl_put: the signature and body of this method changed
between 2.0 and 3.0.
This commit represents the conversion of the usnic BTL from verbs to
libfabric.
For the moment, libfabric is embedded in Open MPI (currently in the
usnic BTL). This is because the libfabric API is still changing, and
also has not yet been released. Ultimately, this embedded copy of
libfabric will likely disappear and the usnic BTL will rely on an
external installation of libfabric.
New configure options:
* --with-libfabric: will cause configure to fail if libfabric support
cannot be built
* --without-libfabric: will prevent libfabric support from being built
* --with-libfabric=DIR: use an external libfabric installation
* --with-libfabric-libdir=LIBDIR: when paired with --with-libfabric=DIR,
use LIBDIR for the libfabric installation library dir
The --with-libnl3[-libdir] arguments are now gone.
