Finish up crypto, minus the legacy modules we haven't been touching much.

Change-Id: I0e9e1999a627aed5fb14841f8a2a7d0b68398e85
Reviewed-on: https://boringssl-review.googlesource.com/4517
Reviewed-by: Adam Langley <agl@google.com>

The 2 arg OpenSSL sk_find() returned -1 on error and >= 0 on
success.  BoringSSL's 3 arg sk_find() returns -1 if the sk argument
is NULL, 0 if the item is not found, and 1 if found.

In practice, all callers of the sk_find() macros in BoringSSL only
check for zero/non-zero.  If sk is ever NULL, it looks like most
callers are going to use uninitialized data as the index because
the return value check is insufficient.

Change-Id: I640089a0f4044aaa8d50178b2aecd9c3c1fe2f9c
Reviewed-on: https://boringssl-review.googlesource.com/4500
Reviewed-by: Adam Langley <agl@google.com>

The next change imported from upstream needs this function.

Change-Id: I547efa1f7f46f0558e88047837a26ede32b19275

Including string.h in base.h causes any file that includes a BoringSSL
header to include string.h. Generally this wouldn't be a problem,
although string.h might slow down the compile if it wasn't otherwise
needed. However, it also causes problems for ipsec-tools in Android
because OpenSSL didn't have this behaviour.

This change removes string.h from base.h and, instead, adds it to each
.c file that requires it.

Change-Id: I5968e50b0e230fd3adf9b72dd2836e6f52d6fb37
Reviewed-on: https://boringssl-review.googlesource.com/3200
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

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.)