distclean doesn't remove nodist BUILT_SOURCES

[Stepan Kasal]

Hello,
  I have some files in BUILT_SOURCES and in nodist_xxx_SOURCES,
so that they are not distributed.
  I'd expect that ``make distclean'' would remove them, but that's
not the case.  (I had to add a distclean-local rule to remove them,
so that ``make distclean'' gets the tree to the original state.)

  Isn't this a bug in automake?  (I use automake-1.9.2.)

Thanks,
        Stepan Kasal