CMake 3.27 deprecates compatibility with CMake < 3.5. Update tests that
do not cover older interfaces to avoid the deprecation warning.
Follow the pattern from:
* commit 7b07ccdd2b (Tests/*Only: Update cmake_minimum_required versions,
2020-06-15, v3.19.0-rc1~629^2~1)
* commit 72e7c45e98 (Tests: Bump CMake minimum required in tests to 2.8.12,
2020-12-22, v3.20.0-rc1~224^2)
* commit f6b4db365a (Tests: bump cmake_minimum_required version to 2.8.12,
2021-04-04, v3.21.0-rc1~372^2)
Also remove explicit `cmake_policy` settings made redundant by the
version.
Since 3.19, CMake generates a deprecation warning when using a minimum
version less than 2.8.12. This eliminates those warnings generated
during tests, which are typically hidden from the user and developer but
are being generated nonetheless.
Shorten the add_definitions command test directory and target names to
avoid creating really long paths that fail with some tools on Windows.
While at it, remove unnecessary project() command calls.
The VS 6 IDE does not like spaces in definition values so CMake drops
them and warns. The Tests/CompileDefinitions test C code that looks for
the dropped definitions already knows to skip them, but CMake still
warns. Silence the warnings by avoiding such values in the first place
on VS 6.
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.
Brad King