I have encountered an issue when using the default auto-build feature, as it does not pass the CMAKE_CXX_FLAGS parameter to cmake. Upon closer inspection, I found that the cpp/tools/do-prebuild.sh script uses a fixed CXXFLAGS=-fpermissive.

It would be beneficial if the script could allow reading the CXXFLAGS configuration from environment variables, like this:

export CXXFLAGS="'${CXXFLAGS:-} -fpermissive'"

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