Description: Workaround to fix compilation under kfreebsd-amd64
  This patch is workaround to fix a compilation error under kfreebsd-amd64
  Includes <cerrno> on top in order to avoid the inclusion of <errno.h>.
Author: Leonardo Montecchi <lmontecchi@montex.org>
Last-Update: <2019-08-22>

--- a/src/TonemappingOperators/mantiuk08/display_function.h
+++ b/src/TonemappingOperators/mantiuk08/display_function.h
@@ -32,6 +32,10 @@
 #ifndef DISPLAY_FUNCTION_H
 #define DISPLAY_FUNCTION_H
 
+#if defined(__FreeBSD_kernel__) && __x86_64__
+#include <cerrno>       // Fixes compilation on kfreebsd-amd64 on Debian
+#endif
+
 #include <cstdio>
 #include "../../opthelper.h"