Initial CMake build support

[externl]

This PR adds the initial support for building the C++ demos using CMake. The end goal is to use replace the Make and MSBuild based build systems with this.

Currently I've only added support for greeter and greeterAsync.

We're using standard cmake setup which is different from our usual Make and MSBuild build systems. The compiled binaries will be available in the build directory (in a nested Release/Debug folder for multi config build systems).

Configure cmake:

cd Ice/greeter/
mkdir build
cd build
cmake ..

Build:

cmake --build .

Note:

Ice/greeter uses a helper function I wrote (similar to one protobuf has)
Ice/greeterAsync does the slice compilation "by hand".

I think having this function will be useful for more complicated builds. I'm undecided if we should use it in our demos.

Note 2:

The build does not include lots of compiler build flags as it's not a best practice as they're often highly compiler dependent and are unnecessary for users. See https://alexreinking.com/blog/how-to-use-cmake-without-the-agonizing-pain-part-2.html

In the future we can add a profile for us to use for building with all of the warnings enabled.

EDIT:

• Removed the top level CMakeLists.txt. It was just making things more painful.
• Always use the helper function

Copilot reviewed 1 out of 6 changed files in this pull request and generated no comments.

Files not reviewed (5)

• .vscode/settings.json: Language not supported
• cpp/CMakeLists.txt: Language not supported
• cpp/Ice/greeter/CMakeLists.txt: Language not supported
• cpp/Ice/greeterAsync/CMakeLists.txt: Language not supported
• cpp/cmake/common.cmake: Language not supported

[externl]

This sets the cmake variable Ice_HOME to our usual "expected" location, adjacent to the ice-demos dir. This way you don't need to open visual studio code with the correct environment.

Copilot reviewed 4 out of 9 changed files in this pull request and generated no comments.

Files not reviewed (5)

• .vscode/settings.json: Language not supported
• cpp/Ice/greeter/CMakeLists.txt: Language not supported
• cpp/Ice/greeterAsync/CMakeLists.txt: Language not supported
• cpp/Ice/secure/CMakeLists.txt: Language not supported
• cpp/cmake/common.cmake: Language not supported

Comments suppressed due to low confidence (2)

cpp/Ice/greeter/README.md:18

• The line '-server' should be removed completely to avoid confusion.

-server

cpp/Ice/greeter/README.md:32

• The line '-client' should be removed completely to avoid confusion.

-client

[bernardnormier]

The default is Debug? Should we just show the default?

[externl]

From what I read cmake doesn't have a default and it's all about the generator's default which apparently in several cases is debug.

[bernardnormier]

Should this be:

build\Release\server

?

[externl]

Yes.

[externl]

Note that this pathing is really generator specific and not OS specific. But since we're showing the defaults which are Make and "Visual Studio" I think it's fine to phrase like this.

[pepone]

Suggested change

	./build/Release/client
	.\build\Release\client