2017-07-02 4:17 GMT+08:00 Paul Eggert <eggert@cs.ucla.edu>:

On 06/29/2017 09:33 AM, Eli Zaretskii wrote:

Paul, isn't it strange that waitpid exits with errno = ECHILD when it
waits for a specific PID?  What can we do against such calamities?
accept it like we do with EINTR?

It's apparently a bug in macOS and I installed a workaround for it in master, as commit 7c951fd51832badb09055a8e177f8ec358cbbdcf dated 2017-05-19.