dummy: fixup warnings

src/dummy/i_system.c

@@ -14,13 +14,18 @@ size_t I_GetFreeMem(size_t *total)
 	return 0;
 }
 
-void I_Sleep(UINT32 ms){}
+void I_Sleep(UINT32 ms)
+{
+	(void)ms;
+}
 
-precise_t I_GetPreciseTime(void) {
+precise_t I_GetPreciseTime(void)
+{
 	return 0;
 }
 
-UINT64 I_GetPrecisePrecision(void) {
+UINT64 I_GetPrecisePrecision(void)
+{
 	return 1000000;
 }
 
@@ -182,10 +187,12 @@ const char *I_ClipboardPaste(void)
 
 size_t I_GetRandomBytes(char *destination, size_t amount)
 {
+	(void)destination;
+	(void)amount;
 	return 0;
 }
 
-void I_RegisterSysCommands(void) {}
+void I_RegisterSysCommands(void){}
 
 void I_GetCursorPosition(INT32 *x, INT32 *y)
 {