In commit b237dbd8 (Xcode: Fix object library references in
multi-project trees, 2012-08-03) we accidentally enabled CXX in the
subdiretories of this test by invoking project() with only one argument.
The top-level directory of the test enables only C, so do this in the
subdirectories too.
In cmGlobalXCodeGenerator::Generate we generate a .xcodeproj for each
directory in the tree containing a project() command. First we
iteratively use SetGenerationRoot to add "ALL_BUILD" and other targets
to each project. This leaves "CurrentProject" set to the last project
when we invoke cmGlobalGenerator::Generate, which is not the same as the
top-level project if any subdirectories invoke the project() command.
When cmGlobalGenerator::Generate reaches CreateGeneratorTargets it
constructs cmGeneratorTarget and calls ComputeTargetObjects exactly once
per target. In this context the value of CurrentProject is undefined so
we cannot pass it to GetObjectsNormalDirectory. Use "$(PROJECT_NAME)"
instead so it will adapt automatically to each project.
Also teach Tests/ObjectLibrary to cover this case.
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.
