libmsgpack.[a|so] is the library file for C++.
libmsgpackc.[a|so] is the library file for C.
Since version 1.0.0, the C++ parts of msgpack-c is a header only
library. So libmsgpack.* shouldn't be generated.
On the autotools building environment, removed libmsgpack.*
generation. On the cmake building environment, replaced libmsgpack.*
with libmsgpackc.* and set so-version to 2.0.0.
Sam Doshi