poppler: Add required patch

packages/poppler/poppler-Form.cc.patch

@@ -0,0 +1,13 @@
+Include <ctype.h> for isxdigit(3).
+
+diff -u -r ../poppler-0.59.0/poppler/Form.cc ./poppler/Form.cc
+--- ../poppler-0.59.0/poppler/Form.cc	2017-08-16 00:16:09.000000000 +0200
++++ ./poppler/Form.cc	2017-09-11 20:06:45.434163003 +0200
+@@ -29,6 +29,7 @@
+ 
+ #include <set>
+ #include <limits>
++#include <ctype.h>
+ #include <stddef.h>
+ #include <string.h>
+ #include "goo/gmem.h"