When a wrapper method calls the real implementation, it's not possible to use a
tail call when dynamic linking on ppc64le. The bad scenario is when a local
call is made to the wrapper: the wrapper will call the implementation, which
might be in a different module and so set the TOC to the appropriate value for
that module. But if it returns directly to the wrapper's caller, nothing will
reset it to the correct value for that function.

Change-Id: Icebf24c9a2a0a9a7c2bce6bd6f1358657284fb10
Reviewed-on: https://go-review.googlesource.com/23468Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>