+ elif int(gcc[0]) >= 5 and int(gcc[0]) <= 8
+ # There appears to be a GCC bug which lingered from major versions 5--8 and which
+ # flags up these warnings all over the place in boost::optional.
+ # This seems to be the only practical way to hide it.
+ conf.env.append_value('CXXFLAGS', ['-Wno-maybe-uninitialized'])