--- ./filter/pdf.cxx.orig	2019-08-30 04:19:22.000000000 -0500
+++ ./filter/pdf.cxx	2019-09-01 13:35:31.908840669 -0500
@@ -19,6 +19,7 @@
 #include <config.h>
 #include "pdf.h"
 #include <vector>
+#include <cstring>
 #include <string>
 #include <qpdf/QPDF.hh>
 #include <qpdf/QPDFObjectHandle.hh>