The original code is the Network Security Services (NSS), licensed under
the MPL/GPL/LGPL tri-license (http://www.mozilla.org/MPL/).

We extracted the SHA-256 source files, eliminated unneeded dependencies,
deleted or commented out unused code, and tweaked them for Chrome's source
tree.  sha512.c is renamed sha512.cc so that it can include Chrome's C++
header "base/basictypes.h".  We define NOUNROLL256 to reduce the object code
size.

In blapi.h and sha512.cc, replaced uint32 by unsigned int so that they can
be compiled with -DNO_NSPR_10_SUPPORT.  NO_NSPR_10_SUPPORT turns off the
definition of the NSPR 1.0 types int8 - int64 and uint8 - uint64 to avoid
conflict with the same-named types defined in "base/basictypes.h".
