Add support for arbitrary TLS extensions.

Contributed by Trevor Perrin.
diff --git a/test/testssl b/test/testssl
index 242cb0a..6141688 100644
--- a/test/testssl
+++ b/test/testssl
@@ -30,6 +30,8 @@
   extra="$4"
 fi
 
+serverinfo="./serverinfo.pem"
+
 #############################################################################
 
 echo test sslv2
@@ -176,6 +178,14 @@
 $ssltest -bio_pair -tls1 -npn_client -npn_server -num 2 || exit 1
 $ssltest -bio_pair -tls1 -npn_client -npn_server -num 2 -reuse || exit 1
 
+#############################################################################
+# Serverinfo tests
+
+$ssltest -bio_pair -tls1 -serverinfo_file $serverinfo || exit 1
+$ssltest -bio_pair -tls1 -serverinfo_file $serverinfo -serverinfo_sct || exit 1
+$ssltest -bio_pair -tls1 -serverinfo_file $serverinfo -serverinfo_tack || exit 1
+$ssltest -bio_pair -tls1 -serverinfo_file $serverinfo -serverinfo_sct -serverinfo_tack || exit 1
+
 if ../util/shlib_wrap.sh ../apps/openssl no-srp; then
   echo skipping SRP tests
 else