Configure ACE/TAO Directly Using CMake

[iguessthislldo]

https://github.com/DOCGroup/ACE_TAO/issues/266 should be considered the upstream issue, but this documents the issue from our perceptive.

Right now, when building OpenDDS with CMake, if you don't pass OPENDDS_ACE, it will attempt to download and configure ACE/TAO using MPC (get_ace_tao.cmake, build_ace_tao.cmake, configure_ace_tao.pl). This workaround works in basic cases and I was optimistic about it at first, but every single build parameter has to be translated from CMake to MPC/Make/MSBuild and every platform has to be hardcoded. This caused has problems when the CMake support was developed, specifically trying to make the building of ACE/TAO seamless, and has caused more issues since the CMake support was released (See #4381, #4375, #4478, #4531, #4328).

This would also allow allow easy installation of ACE/TAO along side OpenDDS, including on Windows. Right now OpenDDS builds ACE/TAO, but doesn't install it.

The proper solution to these and the inevitable future problems with the current approach is to cut MPC out of the build process entirely and add proper CMake support to ACE/TAO. There's a couple of ways we could go about it:

1. OpenDDS's CMakeLists.txt were essentially written from scratch. This is possible but daunting for the tests. For ACE/TAO this is daunting for not just the tests, but all the libraries and programs sitting around. This almost certainly not what we're going to do.
2. Build on @ocielliottc's work in https://github.com/DOCGroup/MPC/pull/164. This still requires MPC so would need to be changed to the point where it can generate independent CMakeLists.txt files that can be committed.
3. Build on @huangminghuang's work in https://github.com/huangminghuang/ACE_TAO/tree/cmake and https://github.com/huangminghuang/OpenDDS/tree/cmake. This used a python program separate from MPC to generate the CMake projects.

I created a proof of concept of 1 (ACE_TAO, OpenDDS) in order to test what's needed for IDL generation for TAO. This can build a subset of ACE/TAO and OpenDDS needed for the RTPS Devguide example and run it all in less than 45 seconds on my machine. This requires Ninja and has only been tested on Ubuntu.

git clone https://github.com/iguessthislldo/OpenDDS --branch igtd/pure-cmake-poc --depth 1
cd OpenDDS
git clone https://github.com/iguessthislldo/ACE_TAO --branch igtd/pure-cmake-poc --depth 1
cmake -S . -B build -G Ninja -DCMAKE_UNITY_BUILD=TRUE && cmake --build build --verbose
(cd build/DevGuideExamples/DCPS/Messenger && ctest --verbose)

[iguessthislldo]

Some more thoughts that would probably need to be addressed regardless of how we do this:

• How much platform support is getting ported to CMake? As a baseline, I'd imagine we'd ensure it's what we support now in OpenDDS with CMake: Windows, macOS, Linux, and Android. It'd be great if we could include iOS, but I don't know what building that in CI looks like.
• Ideally we should have automated way to include the information from test list files in the test CMakeLists.txt files so ctest works. This would probably require a lot of help because the difference between how ctest and auto_run_tests.pl work is pretty large. This would help a ton with #4579.
• If ACE/TAO supports imported targets from an MPC build like our original CMake support:
  • If ACE/TAO gets its own copy of import_common.cmake, are we using theirs or are we using ours?
  • Same question but with invoking tao_idl, do we use their equivalent functions or our own?
  • Do we renamed our imported target names, like ACE::ACE?
• If ACE/TAO doesn't have imported targets, do we require that ACE/TAO be built using CMake if OpenDDS is being built using CMake? This would make things easier because it's one less use case for imported_common.cmake.