--- a/include/img.h
+++ b/include/img.h
@@ -27,7 +27,7 @@
   U8 *pixels;
 } img_t;
 
-img_t *IMG_SPLASH;
+extern img_t *IMG_SPLASH;
 
 #endif
 
--- a/src/dat_snd.c
+++ b/src/dat_snd.c
@@ -19,14 +19,14 @@
 
 sound_t *WAV_WAA;
 sound_t *WAV_BOMB;
-sound_t *WAV_BULLET;
-sound_t *WAV_WALK;
-sound_t *WAV_JUMP;
+extern sound_t *WAV_BULLET;
+extern sound_t *WAV_WALK;
+extern sound_t *WAV_JUMP;
 sound_t *WAV_TING;
-sound_t *WAV_BOMBSHHT;
-sound_t *WAV_BONUS;
+extern sound_t *WAV_BOMBSHHT;
+extern sound_t *WAV_BONUS;
 sound_t *WAV_SHHT;
-sound_t *WAV_BOX;
+extern sound_t *WAV_BOX;
 sound_t *WAV_DDDING;
 
 #endif /* ENABLE_SOUND */