With GCC 4.9 and -O2 (and only -O2, -O1 and -O3 didn't trigger it), the
Poly1305 code can end up writing to an unaligned address otherwise and
that triggers a bus error on ARM.

Change-Id: Ifbeb7e2066a893d91d6f63c6565bac7d5542ef81
Reviewed-on: https://boringssl-review.googlesource.com/2850
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>