PK: fix support for ECKEY_DH
diff --git a/include/polarssl/pk_wrap.h b/include/polarssl/pk_wrap.h
index 7d2c3dd..a24fbd1 100644
--- a/include/polarssl/pk_wrap.h
+++ b/include/polarssl/pk_wrap.h
@@ -38,6 +38,7 @@
 
 #if defined(POLARSSL_ECP_C)
 extern const pk_info_t eckey_info;
+extern const pk_info_t eckeydh_info;
 #endif
 
 #if defined(POLARSSL_ECDSA_C)