you can make use of bonus_script to grant custom sc bonuses without need to touch the source code.
*bonus_script "<script code>",<duration>{,<flag>{,<type>{,<status_icon>{,<char_id>}}}};
This command will attach a script to a player for a given duration, in seconds.
After that time, the script will automatically expire. The same bonus cannot be
stacked. By default, this bonus will be stored on `bonus_script` table when player
logs out.
Flags (bitmask):
1 : Remove when dead.
2 : Removable by Dispell.
4 : Removable by Clearance.
8 : Remove when player logs out.
16 : Removeable by Banishing Buster.
32 : Removable by Refresh.
64 : Removable by Lux Anima.
128 : Remove when Madogear is activated or deactivated.
256 : Remove when receive damage.
512 : Script is permanent, cannot be cleared by bonus_script_clear.
1024: Force to replace duplicated script by expanding the duration.
2048: Force to add duplicated script. This flag cannot be stacked with 1024,
if both are defined, 1024 will be checked first and ignore this flag.
Types:
This will be used to decide negative or positive buff for 'debuff_on_logout'.
0: Ignore the buff type and won't be removed if the flag is not &8 (Default)
1: Buff
2: Debuff
Status_icon: See "Status Icon" section in 'src/map/script_constants.hpp'. Default is SI_BLANK (-1).
bonus_script "{ bonus bStr,5; }",60;