libmsgpack was the old C++ library provided by msgpack-c. The C library
is libmsgpackc.
The C++ support became header-only, but there was a bug
(msgpack/msgpack-c#395) wherein using msgpack-c's CMake build system
would only install libmsgpack instead of libmsgpackc.
Searching for both libraries, but preferring libmsgpackc, allows for
building against older msgpack-c releases and prepares for the upcoming
msgpack-c release which fixes the aforementioned issues.
Signed-off-by: James McCoy <jamessan@jamessan.com>
Using msgpack v5 will let nvim be more compatible with msgpack libraries for
other platforms.
This also replaces "raw" references by "bin" which is the new name for msgpack
binary data type