'autoinst' does not terminate

[Akira Kakuto]

Dear Uwe Siart,

> Since a couple of days (don't know the precise date) 'autoinst' does not
> work correctly for me. When I run it on an OTF where it used to work
> earlier it hangs and does not return to the command prompt.

autoinst of $VERSION = '20190712'
seems to work on Windows.

Newer versions than '20190712' use
IPC::Open3 ();
and
waitpid($pid, 0);
for otftotfm.

The waitpid($pid, 0) seems to be very unstable on perl
for Windows.
It sometimes succeeds and very often it does not exit
in the case of autoinst.

Thanks,
Akira