The Watcom compiler interprets "-DB" as option
-db generate browsing information
so define "A_DEF" and "B_DEF" instead of just "A" and "B".
Skip CMAKE_SHARED_LIBRARY_C_FLAGS for Watcom because it is set to
-bd build Dynamic link library
which adds a DLL entry point to each object.
Add "ObjectLibrary" test to build and use OBJECT libraries. Build
multiple object libraries in separate directories with different flags.
Use a custom command to generate a source file in one OBJECT library.
Reference the OBJECT libraries for inclusion in a STATIC library, a
SHARED library, and an EXECUTABLE target. Use the static and shared
libraries each in executables that end up using the object library
symbols. Verify that object library symbols are exported from the
shared library.
Brad King