mangling type_info for builtin types

[Alex Samuel]

Hi,

As far as I can tell, the mangling specification provides no way of
mangling the type_info of a builtin type, e.g. the result of 
typeid (int).

For class C, the typeinfo struct name would be mangled `_ZN1CTIE'.
I'd guess that the typeinfo for int would then be `_ZNiTIE'.  This
would require augmenting the <compound-prefix> production to have
alternatives for non-class/namespace types:

    <compound-prefix> ::= <path-component> [<template-args>]
                      ::= <builtin-type>
                      ::= <function-type>
                      ::= <array-type>
                      ::= <pointer-to-member-type>

Regards
Alex