RISC-V glibc Port v1

[Joseph Myers]

General observations, to be addressed globally for the patch series:

* All new files should have a descriptive comment on their first line, 
before the copyright notice.

* All copyright notices should use a single range of years, <year>-2017, 
assuming the first year is no earlier than 1990.

* No "Contributed by" notices in any new files.

* All license notices should have a URL, not an old FSF postal address.

* Please include changes to build-many-glibcs.py to make it build glibc 
for all the supported ABI variants (I think from this patch series there 
are six different mutually incompatible ABI variants supported?).  Make 
sure that, if you use your patched Linux kernel sources, all six variants, 
as built with build-many-glibcs.py, both build cleanly and produce clean 
results for the compilation parts of the glibc testsuite, with both GCC 7 
and current GCC trunk.  (For variations that are instruction set variants 
rather than ABI variants, it's at your discretion whether it's useful to 
build glibc for such variants as well; that depends on whether doing so 
covers significant extra code in glibc that would not otherwise be built.)

* Also include details of the full testsuite results, including execution 
tests (which build-many-glibcs.py can't run), for all ABI variants again, 
in the next submission of the port.

-- 
Joseph S. Myers
joseph@codesourcery.com