Add CRYPTO_BUFFER and CRYPTO_BUFFER_POOL.

These structures allow for blobs of data (e.g. certificates) to be
deduplicated in memory.

Change-Id: Iebfec90b85d55565848a178b6951562b4ccc083e
Reviewed-on: https://boringssl-review.googlesource.com/11820
Reviewed-by: Adam Langley <alangley@gmail.com>
Commit-Queue: Adam Langley <alangley@gmail.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

util/doc.config

diff --git a/util/doc.config b/util/doc.config
index e7cfa82..f3f3d52 100644
--- a/util/doc.config
+++ b/util/doc.config
@@ -14,6 +14,7 @@
       "include/openssl/lhash.h",
       "include/openssl/mem.h",
       "include/openssl/obj.h",
+      "include/openssl/pool.h",
       "include/openssl/rand.h",
       "include/openssl/stack.h",
       "include/openssl/time_support.h"