Macros for typtype (was Re: Arrays of Complex Types)

I wrote:
> David Fetter <david(at)fetter(dot)org> writes:
>> What parts of the code would need a once-over?

> A lot :-( ... probably every place that touches typtype or typelem would
> need at least a look. It'd be a good idea to take the opportunity to
> start using macros for the values of typtype, as we do for relkind but
> for some reason never adopted for typtype.

I just realized that I need to check every usage of typtype to be sure
that the enums patch is sane. So, barring objection, I intend to take
this opportunity to make the code stop referring directly to 'b', 'c'
etc whereever possible. Any objections to these names?

#define TYPTYPE_BASE 'b'
#define TYPTYPE_COMPOSITE 'c'
#define TYPTYPE_DOMAIN 'd'
#define TYPTYPE_ENUM 'e'
#define TYPTYPE_PSEUDO 'p'

regards, tom lane