exec-missing: exit(0)
--OR--
(exec-missing) begin
+(exec-missing) exec("no-such-file"): -1
+(exec-missing) end
+exec-missing: exit(0)
+--OR--
+(exec-missing) begin
load: no-such-file: open failed
no-such-file: exit(-1)
(exec-missing) exec("no-such-file"): -1