diff --git a/cryptography/hazmat/backends/openssl/crypto.py b/cryptography/hazmat/backends/openssl/crypto.py
index 8749e2e..835be14 100644
--- a/cryptography/hazmat/backends/openssl/crypto.py
+++ b/cryptography/hazmat/backends/openssl/crypto.py
@@ -28,6 +28,9 @@
 """
 
 FUNCTIONS = """
+unsigned long SSLeay(void);
+const char *SSLeay_version(int);
+
 void CRYPTO_free(void *);
 int CRYPTO_mem_ctrl(int);
 int CRYPTO_is_mem_check_on(void);
diff --git a/cryptography/hazmat/backends/openssl/ssl.py b/cryptography/hazmat/backends/openssl/ssl.py
index fb3b17e..596db05 100644
--- a/cryptography/hazmat/backends/openssl/ssl.py
+++ b/cryptography/hazmat/backends/openssl/ssl.py
@@ -246,6 +246,7 @@
 /* SNI APIs were introduced in OpenSSL 1.0.0.  To continue to support
  * earlier versions some special handling of these is necessary.
  */
+const char *SSL_get_servername(const SSL *, const int);
 void SSL_set_tlsext_host_name(SSL *, char *);
 void SSL_CTX_set_tlsext_servername_callback(
     SSL_CTX *,