Previously, gcm.c contained a lot of workarounds for cases where BSWAP8
wasn't defined. Rather than handle this in each place, just make it
always available.

While we're here, make these macros inline functions instead and rename
them to something less likely to collide.

Change-Id: I9f2602f8b9965c63a86b177a8a084afb8b53a253
Reviewed-on: https://boringssl-review.googlesource.com/12479
Commit-Queue: Adam Langley <alangley@gmail.com>
Reviewed-by: Adam Langley <agl@google.com>

gcm_test.cc needs to access the internal GCM symbols. This is
unfortunate because it means that they have to be marked OPENSSL_EXPORT
just for this.

To compensate, modes.h is removed and its contents copied into
crypto/modes/internal.h.

Change-Id: I1777b2ef8afd154c43417137673a28598a7ec30e
Reviewed-on: https://boringssl-review.googlesource.com/6360
Reviewed-by: Adam Langley <alangley@gmail.com>

See https://boringssl-review.googlesource.com/#/c/4832/.

Change-Id: Icf457a2b47bc2d5b84dddc454d5ca8ec328b5169
Reviewed-on: https://boringssl-review.googlesource.com/4860
Reviewed-by: Adam Langley <agl@google.com>

With NO_ASM defined, the recent AEAD changes broke the tests. The
problem is that the generic CBC mode code tests whether in != out and
omits to save the IV, assuming that it'll be able to read the old
ciphertext block.

However, consider the case where out = in - 16:

    1       2      3       4
|-------|-------|------|-------|
    ^       ^
    |       |
   out     in

First time around, 1 = decrypt(2) ^ iv and everything is fine, because
the IV was preconfigured. However, the next iteration of the loop sets
2 = decrypt(3) and tries to XOR it with the contents of the previous
ciphertext block… from 2.

Change-Id: Ibabff430704fad246de132b4d6d514f6a0362734

Everything else.

Change-Id: Iac02b144465b4e7b6d69ea22ff2aaf52695ae732

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>

Initial fork from f2d678e6e8 (1.0.2 beta).

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