diffutils: add --without-included-regex for uclibc builds in 2.8.1

diffutils: add --without-included-regex for uclibc builds in 2.8.1
 - diffutils works out that uclibc is not glibc and automagically
   builds its own regex, this is not good because its own regex
   relies on GNU specific features which are no longer in uclibc
   (svn head), whereas the uclibc regex is actually a copy of the
   glibc one...