diff -u dlls/wininet/internet.h.orig dlls/wininet/internet.h
--- dlls/wininet/internet.h.orig	2008-05-30 16:41:29.000000000 +0200
+++ dlls/wininet/internet.h	2008-06-01 22:45:28.000000000 +0200
@@ -45,6 +45,7 @@
 #undef PKCS7_SIGNER_INFO
 #undef X509_NAME
 #undef X509_CERT_PAIR
+#undef X509_EXTENSIONS
 # include <openssl/ssl.h>
 #undef FAR
 #define FAR do_not_use_this_in_wine