Fix analysis for macros defined in the same namespace

[mk]

Clerk's analysis currently runs macro-expansion in order to derive the dependencies of a given expression. This works fine for macros defined outside the current file / namespace as we're evaluating any requires and are than in turn able to run the macro-expansion step.

For macros defined in the same namespace, this fails, see e.g. #735 (comment).

We should either fix this limitation or document it.