map L_TRIG to alt button

- switches immediately when releases L
- or whenevever L+Z is pressed. Will switch back when L is released.

src/game/player.c

@@ -806,6 +806,8 @@ void playerLoadDefaults(void)
 	g_Vars.currentplayer->prevoverexposurered = 0;
 	g_Vars.currentplayer->prevoverexposuregreen = 0;
 	g_Vars.currentplayer->prevoverexposureblue = 0;
+	g_Vars.currentplayer->amdowntime = 0;
+	g_Vars.currentplayer->altdowntime = 0;
 }
 
 bool playerSpawnAnti(struct chrdata *hostchr, bool force)