exiv2: add patch needed for debug build

packages/exiv2/exiv2json.cpp.patch

@@ -0,0 +1,11 @@
+--- ../exiv2json.cpp.orig	2019-05-31 21:32:41.319959442 +0200
++++ ./samples/exiv2json.cpp	2019-05-31 21:33:11.399959231 +0200
+@@ -236,7 +236,7 @@
+ {
+     Jzon::Object& fs = (Jzon::Object&) nfs;
+     fs.Add("path",path);
+-    char resolved_path[2000]; // PATH_MAX];
++    char resolved_path[PATH_MAX];
+     fs.Add("realpath",realpath(path,resolved_path));
+ 
+     struct stat buf;