Support C++ compilers

Author: dalcinl

include/mpi.h

@@ -3,6 +3,10 @@
 
 #include <stdint.h>
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
 #define MPI_VERSION    4
 #define MPI_SUBVERSION 2
 
@@ -1872,4 +1876,8 @@ int PMPI_T_source_get_info(int source_index, char *name, int *name_len, char *de
 int PMPI_T_source_get_num(int *num_sources);
 int PMPI_T_source_get_timestamp(int source_index, MPI_Count *timestamp);
 
+#if defined(__cplusplus)
+}
+#endif
+
 #endif  /* MPI_H_ABI */