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>

Chromium does not like static initializers, and the CPU logic uses one to
initialize CPU bits. However, the crypto library lacks an explicit
initialization function, which could complicate (no compile-time errors)
porting existing code which uses crypto/, but not ssl/.

Add an explicit CRYPTO_library_init function, but make it a no-op by default.
It only does anything (and is required) if building with
BORINGSSL_NO_STATIC_INITIALIZER.

Change-Id: I6933bdc3447fb382b1f87c788e5b8142d6f3fe39
Reviewed-on: https://boringssl-review.googlesource.com/1770
Reviewed-by: Adam Langley <agl@google.com>

This change removes the previous OpenSSL/NSS hack in PKCS#12 parsing and
limits the hacks purely to the BER->DER conversion function, where they
belong.

PKCS#7 and #12 switch between implicit and explicit tags in different
places and sometimes only implicitly define that they are using implicit
tags. This change fixes a previous confusion where an implicit tag was
thought to be explicit.

Change-Id: Ib68c78cf2a1bfcbf90a296cb98313ab86ed2a1f3
Reviewed-on: https://boringssl-review.googlesource.com/1640
Reviewed-by: Adam Langley <agl@google.com>

Otherwise, in C, it becomes a K&R function declaration which doesn't actually
type-check the number of arguments.

Change-Id: I0731a9fefca46fb1c266bfb1c33d464cf451a22e
Reviewed-on: https://boringssl-review.googlesource.com/1582
Reviewed-by: Adam Langley <agl@google.com>

This function serialises a PKCS#7 structure containing a number of
certificates.

Change-Id: Iaf15887e1060d5d201d5a3dd3dca8d51105ee6d6
Reviewed-on: https://boringssl-review.googlesource.com/1431
Reviewed-by: Adam Langley <agl@google.com>