Any particular reason src/plugins/contrib/clangd_client/clangd_client_wx32_64.cbp has been changed to not use the GNU c++ extensions? I get the change from v17 back v11. Everything else uses gnu++1. The same can be asked of 'clangd_client_wx31_64.cbp'.
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I was informed by an AutoTools builder that debian and Mac builds failed because Clangd_client was using c++17 and that CB AutoTools builds did not support that option.
Being ignorant of AutoTools, I took the easiest option and re-coded anything that required newer than std=c++11 to reduce the code to std=c++11.
std=c++11 is what the messager suggested.