diff -Nuar bluez-5.50/tools/btpclient.c bluez-5.50-fixed/tools/btpclient.c
--- bluez-5.50/tools/btpclient.c	2018-03-10 17:37:07.000000000 +0200
+++ bluez-5.50-fixed/tools/btpclient.c	2018-11-18 09:54:38.916794492 +0200
@@ -29,6 +29,7 @@
 #include <stdlib.h>
 #include <assert.h>
 #include <getopt.h>
+#include <signal.h>
 
 #include <ell/ell.h>