As of SCons 4.0.1, the default value for $LINK is $SMARTLINK, which itself is a function that will use $CXX as linker for C++: https://github.com/SCons/scons/blob/4.0.1/SCons/Tool/link.py#L327-L328 https://github.com/SCons/scons/blob/4.0.1/SCons/Tool/link.py#L54-L76 So we don't need to manually specify the same value as $CXX for $LINK.
debug_symbols=full
debug_symbols=yes