-#if defined(__GNUWIN32__) && !defined(__MINGW32__)
-#define wxFONTENUMPROC int(*)(ENUMLOGFONTEX *, NEWTEXTMETRICEX*, int, LPARAM)
+// I've no idea what __GNUWIN32_OLD__ is. Anyway, I had to add the 2nd condition
+// for Cygwin b20 (JACS)
+#if (defined(__GNUWIN32_OLD__) || defined(__GNUWIN32__)) && !defined(__MINGW32__)
+ #define wxFONTENUMPROC int(*)(ENUMLOGFONTEX *, NEWTEXTMETRICEX*, int, LPARAM)