[#4107] Add missing cstring include for strerror()

diff --git a/src/lib/util/pid_file.cc b/src/lib/util/pid_file.cc
index 7483b35359e98b63748da4673f102cdbf94a8126..085ffd03810f961558069455676c12120084ab14 100644 (file)
--- a/src/lib/util/pid_file.cc
+++ b/src/lib/util/pid_file.cc
@@ -9,6 +9,7 @@
 #include <util/pid_file.h>
 
 #include <cerrno>
+#include <cstring>
 
 #include <fcntl.h>
 #include <signal.h>