https://github.com/synfig/synfig/issues/297
https://github.com/synfig/synfig/commit/a1232fa5834a109b470322061d1a4d7346c04f83
--- ETL/_boxblur.h.orig	2016-11-30 04:59:46.000000000 -0600
+++ ETL/_boxblur.h	2017-01-13 00:38:46.000000000 -0600
@@ -29,6 +29,8 @@
 
 /* === H E A D E R S ======================================================= */
 
+#include <algorithm>
+
 /* === M A C R O S ========================================================= */
 
 /* === T Y P E D E F S ===================================================== */