🚀 go-pugleaf

As came up in connection with a recent Notesfiles failure, popen(3) as
it comes with V7 (etc) has a bug:  it does not close the pipe descriptors
if the fork fails.  The fix (first pointed out by Berry Kercheval of
Zehntel) is to change the code at about line 28 from:

	if(pid == -1)
		return NULL;
to
	if (pid == -1) {
		close(myside);
		close(hisside);
		return NULL;
	}

There is a further bug which I came across in the course of looking at
popen and pclose.  Since there is no way to wait(2) selectively for a
specific process, the return code from pclose is unreliable in the
event of multiple simultaneous popen's or other child processes.