Describe the bug
Calling OS_ModuleUnload() on a statically loaded module will still attempt to call dlclose() but the handle is NULL because no module was loaded. At least on Linux/Glibc this actually causes a segmentation fault.

To Reproduce
Using the CFE framework switch any app (e.g. sample_app) from a regular dynamic app to a static app.
Build and run CFE, then shutdown with CTRL+C.
The shutdown ends up calling OS_DeleteAllObjects() which in turn will trigger this bug - one gets a segfault instead of a clean exit.

Expected behavior
Should shutdown cleanly.

System observed on:
Ubuntu 20.04

Reporter Info
Joseph Hickey, Vantage Systems, Inc.