# hand-written Darwin ABI declarations; pid_t is c_int in the existing bindings.
# Darwin's spawn action and attribute handles are pointers to opaque records.
posix_spawn_file_actions_t :: alias ?*mut anyopaque
posix_spawnattr_t :: alias ?*mut anyopaque

posix_spawnp c_func(
    pid ?*mut c_int,
    file ?*c_char,
    actions ?*posix_spawn_file_actions_t,
    attributes ?*posix_spawnattr_t,
    arguments ?*?*mut c_char,
    environment ?*?*mut c_char,
) c_int

# borrowed process environment; neither the vector nor its strings may be freed.
_NSGetEnviron c_func() ?*mut ?*mut ?*mut c_char