Tests/RunCMake/CXXModules: add module-using examples

This includes a number of examples that should work for various levels
of support in a compiler.

There are a number of tests which are gated on various features in the
compilers. To enable the tests, set `CMake_TEST_MODULE_COMPILATION` to a
comma-separated (to avoid `;`-escaping problems) to the list of features
which are supported:

  - `named`: Named modules are supported.
  - `shared`: Shared libraries with module usage at the API boundary are
    supported.
  - `partitions`: Named module partitions are supported.
  - `internal_partitions`: Named module internal partitions are
    supported.

Additionally, a `CMake_TEST_MODULE_COMPILATION_RULES` file must be
passed which contains the rules for how to build modules using the
provided compiler. It will be included in the tests to provide these
rules. To verify that the file provided works as intended, it must set
`CMake_TEST_CXXModules_UUID` to a specific version to indicate that it
is an expected file.

1 files changed, 9 insertions, 0 deletions

diff --git a/Tests/RunCMake/CXXModules/examples/generated-stderr.txt b/Tests/RunCMake/CXXModules/examples/generated-stderr.txt
new file mode 100644
index 0000000..b9bbf34
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/generated-stderr.txt
@@ -0,0 +1,9 @@
+CMake Warning \(dev\) at CMakeLists.txt:12 \(target_sources\):
+  CMake's C\+\+ module support is experimental.  It is meant only for
+  experimentation and feedback to CMake developers.
+This warning is for project developers.  Use -Wno-dev to suppress it.
+
+CMake Warning \(dev\):
+  C\+\+20 modules support via CMAKE_EXPERIMENTAL_CXX_MODULE_DYNDEP is
+  experimental.  It is meant only for compiler developers to try.
+This warning is for project developers.  Use -Wno-dev to suppress it.