`local ambiguity when calling macro` when using `statics:` and `functions`

[ids1024]

I noticed this testing #22. After updating the doc tests to build, this error occurs.

---- src/lib.rs - (line 8) stdout ----
error: local ambiguity when calling macro `external_library`: multiple parsing options: built-in NTs ident ('sname') or 1 other option.
  --> src/lib.rs:16:5
   |
11 |     functions:
   |     ^^^^^^^^^

functions: can be matched as a static, so it is ambiguous and fails to compile. I presume this will require a breaking change to the macro to use a non-ambiguous syntax.