http://www.synfig.org/issues/thebuggenie/synfig/issues/438
--- a/src/modules/mod_png/trgt_png.cpp
+++ b/src/modules/mod_png/trgt_png.cpp
@@ -39,6 +39,7 @@
 #include <algorithm>
 #include <functional>
 #include <ETL/misc>
+#include <cstring>
 
 #endif