[master] 3e3990d7d Add missing include

[Federico G. Schwindt]

commit 3e3990d7d6feb4ad5315634128f6244788e9fa03
Author: Federico G. Schwindt <fgsch at lodoss.net>
Date:   Wed Nov 14 06:55:09 2018 +0900

    Add missing include

diff --git a/bin/varnishadm/varnishadm.c b/bin/varnishadm/varnishadm.c
index b7b82cbf5..16393ecde 100644
--- a/bin/varnishadm/varnishadm.c
+++ b/bin/varnishadm/varnishadm.c
@@ -52,6 +52,7 @@
 #include <math.h>
 #include <fcntl.h>
 #include <poll.h>
+#include <signal.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>