Zandronum <3.0 does not support actual named scripts, but you can use #define to give names to script numbers:

#define myproject_somescript 301
#define myproject_enter 302

script myproject_somescript (void)
{
    ...
}

script myproject_enter ENTER
{
    ...
}

You can even use these script names in decorate if you define them as decorate constants:

const int myproject_somescript = 301;
const int myproject_enter 302;

And then use them in some actor's code:

        TNT1 A 0 ACS_ExecuteAlways(myproject_somescript, 0)