Move vtimes to a compatibility symbol

I couldn't pinpoint which standard has added it, but no other POSIX
system supports it and/or no longer provide it.  The 'struct vtimes'
also has a lot of drawbacks due its limited internal type size.

I couldn't also see find any project that actually uses this symbol,
either in some dignostic way (such as sanitizer).  So I think it should
be safer to just move to compat symbol, instead of deprecated.  The
idea it to avoid new ports to export such broken interface (riscv32
for instance).

Checked on x86_64-linux-gnu and i686-linux-gnu.