(In reply to Emil Velikov from comment #3)
> I.e. if the _BSD_SOURCE define does not help, then either glibc needs to be
> fixed or the manuals should be updated (the glibc fold might have some
> suggestions) ?

_BSD_SOURCE gets defined if you call AC_USE_SYSTEM_EXTENSIONS from
configure.ac, which gives you the maximal set of defines. It's not safe to just
define the _*_SOURCE macros, since whilst glibc etc treat them as additive, BSD
libcs treat them as restrictive (e.g. defining _BSD_SOURCE gives you a pure BSD
environment without some of the features enabled by, e.g., _XOPEN_SOURCE).