always wait childs to avoid zombies

[iamleot]

Since 4.5 it seems that entr no longer properly wait for childs and
every time an event is triggered it left a zombie.

To reproduce this issue...
On a first terminal, let's create a file and invoke entr:

% touch /tmp/testing-entr ; echo /tmp/testing-entr | ./entr sh -c 'echo $$'

On another terminal let's trigger the running entr:

% echo "foo" >> /tmp/testing-entr
% echo "foo" >> /tmp/testing-entr
% echo "foo" >> /tmp/testing-entr

...and finally - always on the 2nd terminal - let's inspect
corresponding entr process and its zombies:

% ps aux
leot       5696  0.0  0.0   16028  1368 pts/7  S+    6:59PM 0:00.00 ./entr sh -c echo $$
leot      23501  0.0  0.0       0     0 pts/7  Z+         - 0:00.00 (sh)
leot      25071  0.0  0.0       0     0 pts/7  Z+         - 0:00.00 (sh)
leot      29677  0.0  0.0       0     0 pts/7  Z+         - 0:00.00 (sh)

[iamleot]

Forgot to say but I have noticed that on NetBSD/amd64 -current but I would expect other operating systems acting the same.

[eradman]

Good catch; thanks--the latest release is leaving dead processes. Some quick testing seems to indicate that this change is good

[iamleot]

Thank you Eric!