diff --git a/source/audiolib/src/driver_sdl.h b/source/audiolib/src/driver_sdl.h
index 578b1a5df..3c65cc6f2 100644
--- a/source/audiolib/src/driver_sdl.h
+++ b/source/audiolib/src/driver_sdl.h
@@ -18,6 +18,9 @@
 
  */
 
+#ifndef driver_sdl_h__
+#define driver_sdl_h__
+
 #include "compat.h"
 
 int32_t SDLDrv_GetError(void);
@@ -29,3 +32,4 @@ int32_t SDLDrv_PCM_BeginPlayback(char *BufferStart, int32_t BufferSize,
 void SDLDrv_PCM_StopPlayback(void);
 void SDLDrv_PCM_Lock(void);
 void SDLDrv_PCM_Unlock(void);
+#endif // driver_sdl_h__