Fixed Skill Damage Database parsing (#3747)

* Fixed Skill Damage Database parsing
* Fixes #3732.
* Resolved an issue with constants not being properly parsed for the caster type.
Thanks to @RadianFord, @reunite-ro, and @Lemongrass3110!

src/map/skill.cpp

@@ -21618,6 +21618,7 @@ static bool skill_parse_row_changematerialdb(char* split[], int columns, int cur
 static bool skill_parse_row_skilldamage(char* split[], int columns, int current)
 {
 	uint16 id = 0;
+	int caster;
 
 	trim(split[0]);
 	if (ISDIGIT(split[0][0]))
@@ -21628,7 +21629,16 @@ static bool skill_parse_row_skilldamage(char* split[], int columns, int current)
 	id = skill_db_isset(id, __FUNCTION__);
 
 	skill_db[id]->damage = {};
-	skill_db[id]->damage.caster |= atoi(split[1]);
+	trim(split[1]);
+	if (ISDIGIT(split[1][0]))
+		caster = atoi(split[1]);
+	else { // Try to parse caster as constant
+		if (!script_get_constant(split[1], &caster)) {
+			ShowError("skill_parse_row_skilldamage: Invalid caster constant given for skill %d. Skipping.", id);
+			return false;
+		}
+	}
+	skill_db[id]->damage.caster |= caster;
 	skill_db[id]->damage.map |= atoi(split[2]);
 
 	for(int offset = 3, i = 0; i < SKILLDMG_MAX && offset < columns; i++, offset++ ){