png2ico.cpp:133:31: error: ‘memset’ was not declared in this scope
png2ico.cpp:443:34: error: ‘strcmp’ was not declared in this scope

--- a/png2ico.cpp
+++ b/png2ico.cpp
@@ -33,6 +33,7 @@
 
 
 #include <cstdio>
+#include <cstring>
 #include <vector>
 #include <climits>