ENGINE_register_all_complete() will register all implementations of all

algorithms present in all loaded ENGINEs. The result is that if any of
those ENGINEs successfully initialises, and the ENGINE_TABLE_FLAG_NOINIT
flag isn't set, then they will always be used (and cached as defaults) in
preference to software implementations. Ie. accidental auto-detection of
acceleration hardware :-)

This change stops all implementations being automatically registered in
"openssl" sub-commands, so that the "setup_engine()" handler in apps.c
controls which ENGINEs are registered for use. A special case has been
added that will revert to this "auto-detect" logic, ie. if the "-engine"
switch is used as;
   -engine auto

apps/apps.c

@@ -1150,6 +1150,12 @@ ENGINE *setup_engine(BIO *err, const char *engine, int debug)
 
         if (engine)
                 {
+		if(strcmp(engine, "auto") == 0)
+			{
+			BIO_printf(err,"enabling auto ENGINE support\n");
+			ENGINE_register_all_complete();
+			return NULL;
+			}
 		if((e = ENGINE_by_id(engine)) == NULL)
 			{
 			BIO_printf(err,"invalid engine \"%s\"\n", engine);