Shim out EVP_PKEY_check()

Index: lib/openssl_compat.h
--- lib/openssl_compat.h.orig
+++ lib/openssl_compat.h
@@ -35,4 +35,8 @@ EVP_DigestVerify(EVP_MD_CTX *ctx, const unsigned char 
 }
 #endif
 
+#if defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER >= 0x4000000fL
+#define EVP_PKEY_check(ctx) (-2)
+#endif
+
 #endif
