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.)