--- cegui-0.8.7.old/cegui/src/MinizipResourceProvider.cpp
+++ cegui-0.8.7/cegui/src/MinizipResourceProvider.cpp
@@ -48,6 +48,10 @@
 #   define FNMATCH(p, s)    fnmatch(p, s, FNM_PATHNAME)
 #endif
 
+#ifndef Z_OK
+#define Z_OK MZ_OK
+#endif
+
 // Start of CEGUI namespace section
 namespace CEGUI
 {