Fixed some Linux compiler warnings (fixes #1105)

src/map/battle.c

@@ -4286,7 +4286,6 @@ static int64 battle_calc_skill_constant_addition(struct Damage wd, struct block_
 {
 	struct map_session_data *sd = BL_CAST(BL_PC, src);
 	struct map_session_data *tsd = BL_CAST(BL_PC, target);
-	struct status_change *sc = status_get_sc(src);
 	struct status_data *sstatus = status_get_status_data(src);
 	struct status_data *tstatus = status_get_status_data(target);
 	int64 atk = 0;

src/map/script.c

@@ -9960,7 +9960,7 @@ BUILDIN_FUNC(clone)
 	TBL_PC *sd, *msd=NULL;
 	uint32 char_id;
 	int master_id=0,x,y, flag = 0, m;
-	enum e_mode mode;
+	enum e_mode mode = 0;
 	unsigned int duration = 0;
 	const char *mapname,*event;
 

src/map/unit.c

@@ -1245,7 +1245,7 @@ int unit_warp(struct block_list *bl,short m,short x,short y,clr_type type)
 int unit_stop_walking(struct block_list *bl,int type)
 {
 	struct unit_data *ud;
-	const struct TimerData* td;
+	const struct TimerData* td = NULL;
 	unsigned int tick;
 
 	nullpo_ret(bl);