Define GLIBCXX_DEBUG in Debug builds with libstdc++

[nikobockerman]

No description provided.

[Copilot]

Pull request overview

Adds libstdc++ debug-mode compilation support in CI by defining _GLIBCXX_DEBUG for Debug presets, improving runtime checking for STL usage in debug builds.

Changes:

• Introduces a hidden preset (_ci-libstdc++-debug) that provides -D_GLIBCXX_DEBUG via an environment variable.
• Updates Ubuntu libstdc++ Debug CI presets (clang+libstdc++ and gcc+libstdc++) to include that flag in CMAKE_CXX_FLAGS.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (2)

.github/files/CMakeUserPresets.json:151

• _ci-libstdc++-debug sets CMAKE_CXX_FLAGS to only -D_GLIBCXX_DEBUG. Because preset inheritance overwrites cache variables, any preset that inherits this after another preset that sets CMAKE_CXX_FLAGS will silently lose the other required flags (and the current debug presets must work around that by re-stating the full flag list). Prefer keeping this preset to only define the environment variable and let other presets incorporate it into their own CMAKE_CXX_FLAGS.

      "cacheVariables": {
        "CMAKE_CXX_FLAGS": "$env{PRESET_CXX_FLAGS_LIBSTDCPP_DEBUG}"
      }

.github/files/CMakeUserPresets.json:85

• This preset overrides CMAKE_CXX_FLAGS just to add -D_GLIBCXX_DEBUG, which duplicates the base GCC flags and can drift over time. Consider folding $env{PRESET_CXX_FLAGS_LIBSTDCPP_DEBUG} into the shared GCC/libstdc++ preset’s CMAKE_CXX_FLAGS (or another shared preset) so this top-level preset doesn’t need to restate flags.

      "cacheVariables": {
        "CMAKE_CXX_FLAGS": "$env{PRESET_CXX_FLAGS_LIBSTDCPP_DEBUG} $env{PRESET_CXX_FLAGS_GCC_CLANG}"
      }