Adding ARRAY_SIZE macro for getting the size of constant arrays.

Change-Id: Ie60744761f5aa434a71a998f5ca98a8f8b1c25d5
Reviewed-on: https://boringssl-review.googlesource.com/10447
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

ssl/ssl_lib.c

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 9be76be..52701f4 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -2667,7 +2667,7 @@
     {TLS1_3_VERSION, SSL_OP_NO_TLSv1_3},
 };
 
-static const size_t kVersionsLen = sizeof(kVersions) / sizeof(kVersions[0]);
+static const size_t kVersionsLen = OPENSSL_ARRAY_SIZE(kVersions);
 
 int ssl_get_full_version_range(const SSL *ssl, uint16_t *out_min_version,
                                uint16_t *out_fallback_version,