2.25 freeze

[Joseph Myers]

I hope my fixes for build with GCC mainline can be reviewed reasonably 
early in the freeze (and likewise any subsequent fixes needed for further 
GCC mainline changes) so we can have 2.25 working with GCC 7.  Especially 
the patch <https://sourceware.org/ml/libc-alpha/2017-01/msg00151.html> for 
endian-conversion macros, as that could affect user programs, which the 
other three fixes 
<https://sourceware.org/ml/libc-alpha/2017-01/msg00149.html> 
<https://sourceware.org/ml/libc-alpha/2017-01/msg00150.html> 
<https://sourceware.org/ml/libc-alpha/2017-01/msg00167.html> are unlikely 
to do.

-- 
Joseph S. Myers
joseph@codesourcery.com