--- include/openssl/pkcs7.h.orig	2015-07-06 13:26:27.369203527 -0700
+++ include/openssl/pkcs7.h	2015-07-06 13:27:37.637051967 -0700
@@ -69,6 +69,18 @@
 extern "C" {
 #endif

+#if defined(_WIN32) && defined(__WINCRYPT_H__)
+#ifndef LIBRESSL_INTERNAL
+#ifdef _MSC_VER
+#pragma message("Warning, overriding WinCrypt defines")
+#else
+#warning overriding WinCrypt defines
+#endif
+#endif
+#undef PKCS7_ISSUER_AND_SERIAL
+#undef PKCS7_SIGNER_INFO
+#endif
+
 /*
 Encryption_ID		DES-CBC
 Digest_ID		MD5