DISTFILES containing a directory and files in that directory.

DISTFILES containing a directory and files in that directory.

For PR automake/533:
When the source tree contains non-writable files or directories
(as happens during distcheck), and directories or entries
thereof are listed multiple times in variables to be
distributed, then the corresponding directories below $(distdir)
need to be made writable recursively.  Since file modes should
not change, they need to be copied recursively using `cp -f'.

* lib/am/distdir.am: Handle this situation.
* tests/distdir.test: Extend test to those cases.
* NEWS: Update.
Report by Peter Breitenlohner.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>