'functions --copy': added sanity check on new function name.

Now matches function create behaviour, running the new function name through
wcsfuncname() and parser_keywords_is_reserved(), before allowing the copy.

builtin.c

@@ -1471,6 +1471,16 @@ static int builtin_functions( wchar_t **argv )
 			return STATUS_BUILTIN_ERROR;
 		}
 
+		if( (wcsfuncname( new_func ) != 0) || parser_keywords_is_reserved( new_func ) )
+		{
+			sb_printf( sb_err,
+			           _( L"%ls: Illegal function name '%ls'\n"),
+			           argv[0],
+			           new_func );
+			builtin_print_help( argv[0], sb_err );
+			return STATUS_BUILTIN_ERROR;
+		}
+
 		// keep things simple: don't allow existing names to be copy targets.
 		if( function_exists( new_func ) )
 		{

function.c

@@ -226,8 +226,6 @@ int function_copy( const wchar_t *name, const wchar_t *new_name )
 	CHECK( name, 0 );
 	CHECK( new_name, 0 );
 
-	fn_events = 0;
-
 	orig_d = (function_internal_data_t *)hash_get(&function, name);
 	if( !orig_d )
 		return 0;