Found using various (old-ish) versions of gcc.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2940)
(cherry picked from commit aebe9e399109dcde63a1d0328ffdfc5619b49431)