Adding No-op functions required for NodeJS compatability (#1474)

### Description of changes: 
Added OPENSSL_init and SSL_CTX_set_dh_auto as no-op functions to support
compilation with NodeJS. OPENSSL_init does nothing by design and
SSL_CTX_set_dh_auto because DH is not supported with SSL in AWS-LC.

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license and the ISC license.

crypto/crypto.c

@@ -153,4 +153,6 @@ int OPENSSL_init_crypto(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings) {
   return 1;
 }
 
+void OPENSSL_init(void) {}
+
 void OPENSSL_cleanup(void) {}

include/openssl/crypto.h

@@ -177,6 +177,9 @@ OPENSSL_EXPORT void OPENSSL_load_builtin_modules(void);
 OPENSSL_EXPORT int OPENSSL_init_crypto(uint64_t opts,
                                        const OPENSSL_INIT_SETTINGS *settings);
 
+// OPENSSL_init does nothing.
+OPENSSL_EXPORT void OPENSSL_init(void);
+
 // OPENSSL_cleanup does nothing.
 OPENSSL_EXPORT void OPENSSL_cleanup(void);
 

include/openssl/ssl.h

@@ -5159,6 +5159,9 @@ OPENSSL_EXPORT void SSL_set_tmp_dh_callback(SSL *ssl,
                                             DH *(*cb)(SSL *ssl, int is_export,
                                                       int keylength));
 
+// SSL_CTX_set_dh_auto does nothing and returns 0 for error.
+OPENSSL_EXPORT long SSL_CTX_set_dh_auto(SSL_CTX *ctx, int onoff);
+
 // SSL_CTX_set1_sigalgs takes |num_values| ints and interprets them as pairs
 // where the first is the nid of a hash function and the second is an
 // |EVP_PKEY_*| value. It configures the signature algorithm preferences for

ssl/ssl_lib.cc

@@ -2760,6 +2760,10 @@ void SSL_CTX_set_tmp_dh_callback(SSL_CTX *ctx,
 void SSL_set_tmp_dh_callback(SSL *ssl, DH *(*cb)(SSL *ssl, int is_export,
                                                  int keylength)) {}
 
+long SSL_CTX_set_dh_auto(SSL_CTX *ctx, int onoff) {
+    return 0;
+}
+
 static int use_psk_identity_hint(UniquePtr<char> *out,
                                  const char *identity_hint) {
   if (identity_hint != NULL && strlen(identity_hint) > PSK_MAX_IDENTITY_LEN) {