diff --git a/src/alsa.h b/src/alsa.h
index 14df713..009d16e 100644
--- a/src/alsa.h
+++ b/src/alsa.h
@@ -22,6 +22,6 @@
 
 #include "main.h"
 
-drv driver_alsa;
+extern drv driver_alsa;
 
 #endif
diff --git a/src/jack.h b/src/jack.h
index 235f9ba..86ced70 100644
--- a/src/jack.h
+++ b/src/jack.h
@@ -23,6 +23,6 @@
 
 #include "main.h"
 
-drv driver_jack;
+extern drv driver_jack;
 
 #endif
diff --git a/src/pulse.h b/src/pulse.h
index fec3b69..ff51da9 100644
--- a/src/pulse.h
+++ b/src/pulse.h
@@ -23,6 +23,6 @@
 
 #include "main.h"
 
-drv driver_pulse;
+extern drv driver_pulse;
 
 #endif