The optimized implementation sha256_process_x86() is not declared
anywhere, this can be caught by -Wmissing-prototypes option.
Just declare it properly in sha.h.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Copy sha256-x86.c from https://github.com/noloader/SHA-Intrinsics, that
uses the compiler intrinsics to implement the update step with the
native x86_64 instructions.
To avoid dependencies of the reference code and the x86 version, check
runtime support only if the compiler also supports -msha.
Signed-off-by: David Sterba <dsterba@suse.com>