RunCMake.CXXModules fails on Debian_Unstable-Clang-libcxx
Continuation of !7224 (comment 1207856)
The vendored Clang used by the bot is built with -DCLANG_DEFAULT_STD_C=c2x -DCLANG_DEFAULT_STD_CXX=cxx2b
, i.e. it defaults C20 and C++23 without GNU extensions.
Cc @ben.boeckel
Edited by Raul Tambre