Patch to create builtin bcmp

[Richard Earnshaw]

>  > BCMP and bzero aren't ANSI functions.  Should we be treating them
>  > exactly the same as memcmp?  Especially when -pedantic (or whatever
>  > the option is).
>  > R.
> 
> Agreed, that's why they are only activated by !no_nonansi_builtins and
> also set DECL_BUILT_IN_NONANSI.  This is similar to how builtin
> "alloca" and "ffs" are handled.

OK.  I just didn't see that in the patch, sorry.

> So, okay to install?

Not sure it's my place to say.  I've no other problems with it.