Add the possibility to build without the ENGINE framework.

PR: 287

crypto/rand/rand.h

@@ -87,7 +87,9 @@ extern int rand_predictable;
 
 int RAND_set_rand_method(const RAND_METHOD *meth);
 const RAND_METHOD *RAND_get_rand_method(void);
+#ifndef OPENSSL_NO_ENGINE
 int RAND_set_rand_engine(ENGINE *engine);
+#endif
 RAND_METHOD *RAND_SSLeay(void);
 void RAND_cleanup(void );
 int  RAND_bytes(unsigned char *buf,int num);