avformat/rtspcodes: introduce ff_rtsp_averror()

Currently this is another name for ff_http_averror()
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/rtspcodes.h

@@ -25,6 +25,7 @@
 #define AVFORMAT_RTSPCODES_H
 
 #include "libavutil/common.h"
+#include "libavformat/http.h"
 
 /** RTSP handling */
 enum RTSPStatusCode {
@@ -139,4 +140,10 @@ enum RTSPMethod {
     RECORD,
     UNKNOWN = -1,
 };
+
+static inline int ff_rtsp_averror(enum RTSPStatusCode status_code, int default_averror)
+{
+    return ff_http_averror(status_code, default_averror);
+}
+
 #endif /* AVFORMAT_RTSPCODES_H */