--- a/src/nvcontrol/nvcontrol.h
+++ b/src/nvcontrol/nvcontrol.h
@@ -42,7 +42,7 @@
 } NVOptionList;
 
 #define OPTION_LIST_SIZE 27
-NVOptionList option_list[OPTION_LIST_SIZE];
+extern NVOptionList option_list[OPTION_LIST_SIZE];
 int init_nvcontrol();
 NVOptionList *nvcontrol_lookup_option(int option);