1 files changed, 2 insertions, 1 deletions
diff --git a/src/util.h b/src/util.h
index e79c0a0b..8db838eb 100644
--- a/src/util.h
+++ b/src/util.h
@@ -29,6 +29,7 @@
 #include <boost/function.hpp>
 #include <boost/date_time/posix_time/posix_time.hpp>
 #include <boost/filesystem.hpp>
+#include <boost/optional.hpp>
 #include <openjpeg.h>
 #include <string>
 #include <stdint.h>
@@ -81,7 +82,7 @@ extern void add_signature_value (xmlpp::Element* parent, CertificateChain const
 extern void add_signer (xmlpp::Element* parent, CertificateChain const & certificates, std::string const & ns);
 
 extern int base64_decode (std::string const & in, unsigned char* out, int out_length);
-
+extern boost::optional<boost::filesystem::path> relative_to_root (boost::filesystem::path root, boost::filesystem::path file);
 extern std::string tm_to_string (struct tm *);
 extern std::string utc_offset_to_string (int);
 extern std::string ptime_to_string (boost::posix_time::ptime);