diff --git a/thirdparty/minizip/ioapi.h b/thirdparty/minizip/ioapi.h
index f25ab6464..6043d34ce 100644
--- a/thirdparty/minizip/ioapi.h
+++ b/thirdparty/minizip/ioapi.h
@@ -44,6 +44,22 @@
 #include <stdlib.h>
 #include "zlib.h"
 
+/* GODOT start */
+/* Mighty Gentoo saves the day by breaking the API of their zlib.h,
+ * removing this definition of OF(args) for no practical reason
+ * worth breaking compatibility with all projects that embed minizip
+ * while trying not to diverge too much from upstream zlib.
+ * Cf. https://github.com/godotengine/godot/issues/10539
+ *
+ *   "By and large, this is good open source behaviour, and fits with
+ *    the gentoo _don't fuck with upstream's releases_ philosophy"
+ *                                     -- Gentoo philosopher
+ */
+#ifndef OF /* function prototypes */
+ #define OF(args)  args
+#endif
+/* GODOT end */
+
 #if defined(USE_FILE32API)
 #define fopen64 fopen
 #define ftello64 ftell