Fix creation of incremental archives when a subdirectory becomes a mountpoint.

When used with --listed-incrfental and --one-file-system, tar
was unable to cope with directories that had once been part of the
dumped system and became separate mount points afterwards.  The bug
has been reported and a fix proposed by Nathan Stratton Treadway.

* src/incremen.c (procdir): If one_file_system_option is in effect,
clear out dumpdir info from the directory.
* tests/Makefile.am: Add new testcase.
* tests/listed05.at: New testcase.
* tests/testsuite.at (AT_PRIVILEGED_PREREQ): New macro.
include listed05.at.
* THANKS: Update.

tests/testsuite.at

@@ -103,6 +103,16 @@ rm -f $[]$
 test $result -eq 0 && AT_SKIP_TEST
 ])
 
+dnl AT_PRIVILEGED_PREREQ - Skip test if not running at root privileges
+m4_define([AT_PRIVILEGED_PREREQ],[
+echo "test" > $[]$
+chmod 0 $[]$
+cat $[]$ > /dev/null 2>&1
+result=$?
+rm -f $[]$
+test $result -eq 0 || AT_SKIP_TEST
+])
+
 m4_define([AT_TAR_MKHIER],[
 install-sh -d $1 >/dev/null dnl
 m4_if([$2],,,&& genfile --file [$1]/[$2]) || AT_SKIP_TEST])
@@ -186,6 +196,7 @@ m4_include([listed01.at])
 m4_include([listed02.at])
 m4_include([listed03.at])
 m4_include([listed04.at])
+m4_include([listed05.at])
 m4_include([incr03.at])
 m4_include([incr04.at])
 m4_include([incr05.at])