Begin converting URL struct into modern C++ class

dpid/dpi.h

@@ -7,6 +7,12 @@
 #ifndef DPI_H
 #define DPI_H
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+
 #include <unistd.h>      /* for socklen_t */
 #include <sys/socket.h>  /* for socklen_t and AF_LOCAL */
 
@@ -42,4 +48,8 @@ char *a_Dpi_rd_dpi_socket_dir(char *dirname);
 
 char *a_Dpi_srs(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif