The special handling for these names was added in
and the motivation was the C++ standard library.
It turns out some projects like using these names anyway, in particular the
linux kernel. D153946 proposed making this a config option, but there are
some implementation issues with the config system.
As an alternative, this patch tweaks the heuristic so we only drop these symbols
in system headers. This does the right thing for linux and the C++ standard
library, at least.