Exit list handlers registered from dll are not released on DosFreeModule

[Yuri Dario]

Scenario: a DLL register an exit list function using atexit() and the dll is loaded using DosLoadModule?; when the executable calls DosFreeModule?, the exit list handler is not executed nor removed from the list of callbacks. When the executable terminates, it tries to call the dll exit callback and a crash occurs since the dll code is already unloaded from memory.

This doesn't happen when the dll is linked at compile time.

Testcase attached.