[nginx] SSL: support ALPN (IETF's successor to NPN).

[Ruslan Ermilov]

On Thu, Jan 30, 2014 at 12:15:49PM -0800, Piotr Sikora wrote:
> Hey Ruslan,
> 
> > This change breaks compilation with clang on systems
> > where OpenSSL doesn't have ALPN support:
> 
> Good catch! Sorry for introducing this (even though it's clearly a
> false positive)... I usually compile my ALPN & ecdh_auto patches
> against both: OpenSSL-1.0.1 & OpenSSL-1.0.2, but I forgot to do this
> after the last round of "style changes".

NP, and thanks for your numerous contributions!