Add DTLS_with_buffers_method.

WebRTC will need this (probably among other things) to lose crypto/x509
at some point.

Bug: chromium:706445
Change-Id: I988e7300c4d913986b6ebbd1fa4130548dde76a4
Reviewed-on: https://boringssl-review.googlesource.com/18904
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index a5ac325..0eb2cc5 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -192,6 +192,10 @@
  * crypto/x509. */
 OPENSSL_EXPORT const SSL_METHOD *TLS_with_buffers_method(void);
 
+/* DTLS_with_buffers_method is like |DTLS_method|, but avoids all use of
+ * crypto/x509. */
+OPENSSL_EXPORT const SSL_METHOD *DTLS_with_buffers_method(void);
+
 /* SSL_CTX_new returns a newly-allocated |SSL_CTX| with default settings or NULL
  * on error. */
 OPENSSL_EXPORT SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);