// When using configure, the path must be "zlib.h" I don't know
// what other ports (wxMac, wxMotif without configure) need here.
// If we are building with ./configure, we trust the zlib path is
-// given as a -I option.
-#if defined(__WXMSW__) && !defined(HAVE_CONFIG_H)
+// given as a -I option. (confusingly configure defines __GTKSETUPH__)
+#if defined(__WXMSW__) && !defined(__GTKSETUPH__)
#include "..\zlib\zlib.h"
#else
#include "zlib.h"