The immediate in this operation is too large for ARM. GCC will
automatically rewrite it to use bic (where bic does an AND NOT). Clang,
however doesn't, and reasonably throws an error.

This change switches to using bic in the source file, thus making both
happy.

Change-Id: I958fa29b88bffeab20c6ee11660736222a2e6986
Reviewed-on: https://boringssl-review.googlesource.com/4410
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

Change-Id: Id77fb7c904cbfe8172466dff20b6a715d90b806c
Reviewed-on: https://boringssl-review.googlesource.com/1710
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

This change marks public symbols as dynamically exported. This means
that it becomes viable to build a shared library of libcrypto and libssl
with -fvisibility=hidden.

On Windows, one not only needs to mark functions for export in a
component, but also for import when using them from a different
component. Because of this we have to build with
|BORINGSSL_IMPLEMENTATION| defined when building the code. Other
components, when including our headers, won't have that defined and then
the |OPENSSL_EXPORT| tag becomes an import tag instead. See the #defines
in base.h

In the asm code, symbols are now hidden by default and those that need
to be exported are wrapped by a C function.

In order to support Chromium, a couple of libssl functions were moved to
ssl.h from ssl_locl.h: ssl_get_new_session and ssl_update_cache.

Change-Id: Ib4b76e2f1983ee066e7806c24721e8626d08a261
Reviewed-on: https://boringssl-review.googlesource.com/1350
Reviewed-by: Adam Langley <agl@google.com>