__verbose special section support

Fixes for some additional issues I discovered with the patch from #296, related to supporting the `__verbose` section.  It provides some interesting challenges:

1. It contains several static local structs named `descriptor`, some of which may be referenced by the same function.
2. It references several `__func__` static local variables, each of which may reference a different function.  `__func__` is a special gcc-generated static local variable which contains the function name.

Fortunately the fixes are pretty straightforward, because we don't need to correlate the `descriptor` and `__func__` static locals.

Once this PR and #342 are merged, I'll add a modified version of the patch from #296 to the integration test suite.