This generator expression joins a list with a separator. The separator
may contain arbitrary content, such as commas, which is ordinarily a
delimiter in the generator expression syntax.
Because the main file for the dummy-executable and the actual compile
test were both called main.cpp, they were overwriting each other during
in-source builds.
There is no need to do so. Be consistent with include directories and
ensure uniqueness.
This requires changing the API of the cmLocalGenerator::AppendDefines
method, and changing the generators to match.
The test unfortunately can't test for uniqueness, but it at least verifies
that nothing gets lost.
Stephen Kelly
Brad King