With Open MPI 5.0, the decision was made to stop building
3rd-party packages, such as Libevent, HWLOC, PMIx, and PRRTE as
MCA components and instead 1) start relying on external libraries
whenever possible and 2) Open MPI builds the 3rd party
libraries (if needed) as independent libraries, rather than
linked into libopen-pal.
This patch moves libevent from an MCA framework to a stand-alone
library built outside of OPAL. A wrapper in opal/util is provided
to minimize the unnecessary changes in the rest of the code. When
using the internal Libevent, it will be installed as a stand-alone
libevent.a, instead of bundled in OPAL. Any pre-installed version
of Libevent at or after 2.0.21 is preferred over the internal
version.
Signed-off-by: Brian Barrett <bbarrett@amazon.com>
