* ext/openssl/extconf.rb: check SSL_CTX_set_next_proto_select_cb
function rather than OPENSSL_NPN_NEGOTIATED macro. it exists
even if it is disabled by OpenSSL configuration.
[ruby-core:74384] [Bug #12182]
* ext/openssl/ossl_ssl.c: update #ifdef(s) as above.
* test/openssl/test_ssl.rb: skip NPN tests if NPN is disabled.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54258 b2dd03c8-39d4-4d8f-98ff-823fe69b080e