Enforce NULL context for hardcoded RNG
diff --git a/programs/ssl/ssl_pthread_server.c b/programs/ssl/ssl_pthread_server.c
index fd6ca26..80bb049 100644
--- a/programs/ssl/ssl_pthread_server.c
+++ b/programs/ssl/ssl_pthread_server.c
@@ -325,6 +325,20 @@
     return( 0 );
 }
 
+#if defined(MBEDTLS_SSL_CONF_RNG)
+int rng_wrap( void *ctx, unsigned char *dst, size_t len );
+
+mbedtls_ctr_drbg_context *rng_ctx_global = NULL;
+int rng_wrap( void *ctx, unsigned char *dst, size_t len )
+{
+    /* We expect the NULL parameter here. */
+    if( ctx != NULL )
+        return( -1 );
+
+    return( mbedtls_ctr_drbg_random( rng_ctx_global, dst, len ) );
+}
+#endif /* MBEDTLS_SSL_CONF_RNG */
+
 int main( void )
 {
     int ret;
@@ -439,7 +453,12 @@
         goto exit;
     }
 
+#if !defined(MBEDTLS_SSL_CONF_RNG)
     mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
+#else
+    rng_ctx_global = &ctr_drbg;
+#endif
+
 #if defined(MBEDTLS_DEBUG_C)
     mbedtls_ssl_conf_dbg( &conf, my_mutexed_debug, stdout );
 #endif