want this:

extern ConVar g_WeaponValue_assault_damage;

getting this:
extern ConVar g_WeaponValue_assault_ damage;

from this:
DECLARE_WEAPON_VALUE(assault, damage);


Using these:
#define WEAPON_PREFIX(weaponname) g_Weapon_##weaponname
#define WEAPON_VALUE_PREFIX(weaponname) g_WeaponValue_##weaponname
#define WEAPON_VALUE(weaponname, valuename) WEAPON_VALUE_PREFIX(weaponname)_##valuename
#define DECLARE_WEAPON_VALUE(weaponname, valuename) extern ConVar WEAPON_VALUE(weaponname, valuename)
#define DEFINE_WEAPON_VALUE(weaponname, valuename,initialvalue) ConVar WEAPON_VALUE(weaponname, valuename)( "weapon_" #weaponname "_" #valuename, #initialvalue, FCVAR_REPLICATED | FCVAR_CHEAT )