[Bara]

https://github.com/Bara/TroubleinTer.../ttt.inc#L1030
Spanner, Axe and Hammer are known as "weapon_melee".

//Edit:

stock int TTT_HasClientMelee(int client)
{
    for(int offset = 0; offset < 128; offset += 4)
    {
        int weapon = GetEntDataEnt2(client, FindSendPropInfo("CBasePlayer", "m_hMyWeapons") + offset);

        if (IsValidEntity(weapon))
        {
            char sClass[32];
            GetEntityClassname(weapon, sClass, sizeof(sClass));

            if ((StrContains(sClass, "melee", false) != -1))
            {
                return weapon;
            }
        }
    }

    return -1;
}