Added externs declarations to header files to handle C++ compilation.

Cleaned up BACnet/IP API a little.

bacnet-stack/ringbuf.h

@@ -52,16 +52,24 @@ struct ring_buffer_t
 };
 typedef struct ring_buffer_t RING_BUFFER;
 
-extern bool Ringbuf_Empty(RING_BUFFER const *b);
-extern char *Ringbuf_Get_Front(RING_BUFFER const *b);
-extern char *Ringbuf_Pop_Front(RING_BUFFER *b);
-extern bool Ringbuf_Put(
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+bool Ringbuf_Empty(RING_BUFFER const *b);
+char *Ringbuf_Get_Front(RING_BUFFER const *b);
+char *Ringbuf_Pop_Front(RING_BUFFER *b);
+bool Ringbuf_Put(
   RING_BUFFER *b, // ring buffer structure
   char *data_element); // one element to add to the ring
-extern void Ringbuf_Init(
+void Ringbuf_Init(
   RING_BUFFER *b, // ring buffer structure
   char *data, // data block or array of data
   unsigned element_size, // size of one element in the data block
   unsigned element_count); // number of elements in the data block
 
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
 #endif