A previous change in BoringSSL renamed ERR_print_errors_fp to
BIO_print_errors_fp as part of refactoring the code to improve the
layering of modules within BoringSSL. Rename it back for better
compatibility with code that was using the function under the original
name. Move its definition back to crypto/err using an implementation
that avoids depending on crypto/bio.

Change-Id: Iee7703bb1eb4a3d640aff6485712bea71d7c1052
Reviewed-on: https://boringssl-review.googlesource.com/4310
Reviewed-by: Adam Langley <agl@google.com>

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>

Write the array literal of all zeros as {0} rather than {}.

Change-Id: If15330d96d019be671d3bcbbdea60c2b3ecc2128
Reviewed-on: https://boringssl-review.googlesource.com/2740
Reviewed-by: Adam Langley <agl@google.com>

See https://tools.ietf.org/html/rfc5869.

Change-Id: I6d012d8c38806df80aa44350d3a86eaff499ac05
Reviewed-on: https://boringssl-review.googlesource.com/2533
Reviewed-by: Adam Langley <agl@google.com>