bug#5962: improving SHA1 using intel SS3 instructions

[Jim Meyering]

Robbins, Aharon wrote:
> http://software.intel.com/en-us/articles/improving-the-performance-of-the-secure-hash-algorithm-1/?cid=sw:dslnews5149

Thanks for the link.
Improving the performance of coreutils' SHA* programs has been
discussed off and on for some time.  Notably, openssl's equivalents
outperform those in coreutils, but portability counts, too,
which means integrating an assembly-based solution takes time.