Use int instead of long for flags

Use int instead of long for flags

As long as symbol_by_value(), show_capab() and togg() support only
int, flags need to fit into int.

Not a problem in practice, because no machine capable of running
Empire has int narrower than 32 bits, and 32 bits suffice.

Some flags members are long instead of int: struct lchrstr member
l_flags, struct natstr member nat_flags, struct mchrstr member m_flags
are long.  Waste of space on machines with long wider than int.
Change them to int.

Rearrange struct lchrstr and struct natstr to avoid holes.