add guard

Author: sshcrack

include/content-streamer.h

@@ -12,6 +12,8 @@
 // write such animations to disk. It is also used in util/video-viewer.cc
 // to write a version to disk that then can be played with the led-image-viewer.
 
+#ifndef RPI_CONTENT_STREAMER_H
+#define RPI_CONTENT_STREAMER_H
 #include <stddef.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -131,3 +133,5 @@ class StreamReader {
   char *header_frame_buffer_;
 };
 }
+
+#endif