Missing prototype.

crypto/modes/modes.h

@@ -83,6 +83,7 @@ size_t CRYPTO_nistcts128_decrypt(const unsigned char *in, unsigned char *out,
 typedef struct gcm128_context GCM128_CONTEXT;
 
 GCM128_CONTEXT *CRYPTO_gcm128_new(void *key, block128_f block);
+void CRYPTO_gcm128_init(GCM128_CONTEXT *ctx,void *key,block128_f block);
 void CRYPTO_gcm128_setiv(GCM128_CONTEXT *ctx, const unsigned char *iv,
 			size_t len);
 void CRYPTO_gcm128_aad(GCM128_CONTEXT *ctx, const unsigned char *aad,