Add __BEGIN_DECLS and __END_DECLS to make libmemstat(3) more C++-friendly.
Add __BEGIN_DECLS and __END_DECLS to make libmemstat(3) more C++-friendly.

MFC after:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase