Fix spacing after qualified pointers when rendering C declarations.

We don't want to print spaces after pointer qualifiers all the time: in
particular, things like "type const pointer to array of int" would print
a space between the "const" and the ")", as in:

  int (* const )[]

Fix that up by eliding the space if (a) the pointer has qualifiers, and
(b) the child is not a null declarator.