Set return of function to void as it doesn't return anything

screenlock.c

@@ -36,7 +36,7 @@ int checkrtcwake();
 void configuresuspendsettingsandwakeupsources();
 time_t convert_rtc_time(struct rtc_time * rtc);
 void die(const char *err, ...);
-int getoldbrightness();
+void getoldbrightness();
 void init_rtc();
 void lockscreen(Display *dpy, int screen, int blank);
 void unblankscreen();
@@ -69,6 +69,7 @@ time_t waketime = 0; //next wakeup time according to the RTC clock
 int slept = 0; //indicates whether the process has slept (crust) or not
 int blanked = 0; //indicated whether the display blanked or not
 
+// Real time clock device
 #define RTC_DEVICE	  "/dev/rtc0"
 
 time_t
@@ -200,7 +201,7 @@ sigterm()
 	exit(0);
 }
 
-int
+void
 getoldbrightness() {
 	char * buffer = 0;
 	long length;