Unit test runner inconsistencies between CI and workstation

[Scottapotamas]

In this particular case, only the workstation seems to demonstrate the issue.
More debugging needed.

Workstation is using gcc version 10.3.0 (Solus) .

   Ceedling:: 0.30.0
      Unity:: 2.5.1
      CMock:: 2.5.2
 CException:: 1.3.2

fails with linker errors relating to the inclusion and use of electricui_private.h variables.

Existing CI system is using gcc version 8.2.0 (Ubuntu 8.2.0-7ubuntu1)

  Ceedling:: 0.28.3
CException:: 1.3.1.18
     CMock:: 2.4.6.217
     Unity:: 2.4.3.122

and can successfully build and pass the tests.

Macbook using clang also passes tests fine.

[Scottapotamas]

As a point of comparison, this issue doesn't occur with the official docker container either, though it's on a slightly older version of gcc (which does seem a bit stricter).

gcc version 9.3.0 (Alpine 9.3.0)

   Ceedling:: 0.31.1
      Unity:: 2.5.4
      CMock:: 2.5.4
 CException:: 1.3.3