Add low-level p256-x86_64 tests.

For the most part, this is with random test data which isn't
particularly good. But we'll be able to add more interesting test
vectors as they come up.

Change-Id: I9c50db7ac2c4bf978d4901000ab32e3642aea82b
Reviewed-on: https://boringssl-review.googlesource.com/12222
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/include/openssl/bn.h b/include/openssl/bn.h
index 01f75ec..764d8c5 100644
--- a/include/openssl/bn.h
+++ b/include/openssl/bn.h
@@ -148,15 +148,17 @@
 #if defined(OPENSSL_64_BIT)
 #define BN_ULONG uint64_t
 #define BN_BITS2 64
-#define BN_DEC_FMT1	"%" PRIu64
-#define BN_DEC_FMT2	"%019" PRIu64
-#define BN_HEX_FMT1	"%" PRIx64
+#define BN_DEC_FMT1 "%" PRIu64
+#define BN_DEC_FMT2 "%019" PRIu64
+#define BN_HEX_FMT1 "%" PRIx64
+#define BN_HEX_FMT2 "%016" PRIx64
 #elif defined(OPENSSL_32_BIT)
 #define BN_ULONG uint32_t
 #define BN_BITS2 32
-#define BN_DEC_FMT1	"%" PRIu32
-#define BN_DEC_FMT2	"%09" PRIu32
-#define BN_HEX_FMT1	"%" PRIx32
+#define BN_DEC_FMT1 "%" PRIu32
+#define BN_DEC_FMT2 "%09" PRIu32
+#define BN_HEX_FMT1 "%" PRIx32
+#define BN_HEX_FMT2 "%08" PRIx64
 #else
 #error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
 #endif