+ Return 0 on success, or -1 on error with `errno' set.
+
+ Note that on MingW, this function does NOT protect DESC from being
+ inherited into spawned children. Instead, either use dup_cloexec
+ followed by closing the original DESC, or use interfaces such as
+ open or pipe2 that accept flags like O_CLOEXEC to create DESC
+ non-inheritable in the first place. */