[Bug libstdc++/59177] steady_clock::now() and system_clock::now do not use the vdso (and are therefore very slow)

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59177

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
For hosted linux --enable-libstdcxx-time can work just fine, just use it.
But, such a change isn't desirable for the branch, e.g. because the fancy
checks require link tests which aren't usable for some bare metal
configurations, might not be the right thing for Solaris or whatever else, etc.
=auto has been introduced exactly to get some reasonably safe defaults
automatically by default.  So, if you want to change anything on the branch,
supposedly it would be partial backport of the =auto stuff, but only limit it
to the most commonly tested targets or something.  Still, I'd say it is better
to just tell people who want it to --enable-libstdcxx-time themselves if they
want.
In the past it has been ABI incompatible option, now hopefully is not.