WL#5041: Eliminate all warnings from server build

Affects: Falcon-9.x   —   Status: Un-Assigned

Warnings generated by GCC are usually quite significant and we should normally
not allow warnings in our builds.  However, the number of warnings currently
prevents us from using the -Werror flag, which will flag all warnings as errors.

This worklog is about eliminating all warnings from the build so that we can
turn on the -Werror flag in pushbuild and catch potential problems earlier.

- Turn on ``-Werror`` in the normal build scripts under ``BUILD/``
- Eliminate all warnings in the code
- Ensure that ``-Werror`` is turned on in a staging tree under PushBuild
  control and push to this tree
- Eliminate all resulting errors.
- Push the staging tree to the main tree and turn on ``-Werror`` there as well.