Oh, you added open.mp include so you have a two solutions:
1. Add #define SAMP_COMPAT before your includes.
2. Find actual callbacks syntax (it's different) on open.mp wiki and just replace it + for weapons id you should use macro definitions (not ID's). Probably textdraws need it too.
First solution is's definitly a good option for you, beacause you don't need change anything in your code. Just add this define SAMP_COMPAT and gamemode should be build succesful.
In line 51910 you have a redefinition of GetWeaponSlot function. It's arleady defined by default.
1. Add #define SAMP_COMPAT before your includes.
2. Find actual callbacks syntax (it's different) on open.mp wiki and just replace it + for weapons id you should use macro definitions (not ID's). Probably textdraws need it too.
First solution is's definitly a good option for you, beacause you don't need change anything in your code. Just add this define SAMP_COMPAT and gamemode should be build succesful.
In line 51910 you have a redefinition of GetWeaponSlot function. It's arleady defined by default.