This is a version of PKCS7_get_certificates but does not require
crypto/x509.

BUG=54

Change-Id: I20152a8d1f3ed866d47e41fe576ea9f442490224
Reviewed-on: https://boringssl-review.googlesource.com/15129
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>

A follow-up change will add a CRYPTO_BUFFER variant. This makes the
naming match the header and doesn't require including x509.h. (Though
like ssl.h and pkcs8.h, some of the functions are implemented with code
that depends on crypto/x509.)

Change-Id: I5a7de209f4f775fe0027893f711326d89699ca1f
Reviewed-on: https://boringssl-review.googlesource.com/15128
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

Previously, public headers lived next to the respective code and there
were symlinks from include/openssl to them.

This doesn't work on Windows.

This change moves the headers to live in include/openssl. In cases where
some symlinks pointed to the same header, I've added a file that just
includes the intended target. These cases are all for backwards-compat.

Change-Id: I6e285b74caf621c644b5168a4877db226b07fd92
Reviewed-on: https://boringssl-review.googlesource.com/1180
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)