[GCC-XML]Producing "_0" ids when parsing <string>

[Brad King]

Dave,

> I hope that this doesn't mean GCC_XML won't have any representation for
> (uninstantiated) templates and their specializations per se, other than
> representing specific instantiations which are classes or functions.

GCC-XML has never had a representation for uninstantiated templates simply
because it hasn't been implemented.  This bugfix today did nothing to
prevent it from having this support in the future.  Pere's problem came
from the dump of a fake instantiation and making it look like a normal
instantiation.  Future support for dumping uninstantiated templates will
have some marker indicating the declaration is a template.

-Brad