[Exolent[jNr]]

It would be better to do this:

#include <amxmodx>
#include <hamsandwich>

#define PLUGIN "NoDieInWater"
#define VERSION "1.0"
#define AUTHOR "tuty"

new g_enabled;

public plugin_init()
{
    register_plugin(PLUGIN, VERSION, AUTHOR);
    RegisterHam(Ham_TakeDamage, "player", "FwdTakeDamage");
    g_enabled = register_cvar("sv_nodieinwater", "1");
}
public FwdTakeDamage(client, inflictor, attacker, Float:damage, damagebits)
{
    return ((damagebits & DMG_DROWN) && get_pcvar_num(g_enabled)) ? HAM_SUPERCEDE : HAM_IGNORED;
}