Take into account chdir_fd when extracting from incremental dumps.

* src/common.h (tar_savedir): New prototype.
* src/misc.c (tar_savedir): New function.
(remove_any_file): Use tar_savedir.
* src/incremen.c (try_purge_directory): Use tar_savedir.
* src/update.c (update_archive): Use tar_savedir.
* tests/incr07.at: New testcase.
* tests/Makefile.am (TESTSUITE_AT): Add new test.
* tests/testsuite.at: Likewise.
* THANKS: Updated.

tests/Makefile.am

@@ -111,6 +111,7 @@ TESTSUITE_AT = \
  incr04.at\
  incr05.at\
  incr06.at\
+ incr07.at\
  indexfile.at\
  ignfail.at\
  label01.at\

tests/incr07.at

@@ -0,0 +1,106 @@
+# Process this file with autom4te to create testsuite. -*- Autotest -*-
+# Test suite for GNU tar.
+# Copyright 2009, 2013 Free Software Foundation, Inc.
+#
+# GNU tar is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# GNU tar is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([incremental restores with -C])
+AT_KEYWORDS([incremental extract incr07])
+
+# Tar 1.26 had problems extracting from incremental restores when given
+# the -C option.  The code in incremen.c:try_purge_directory and
+# misc.c:remove_any_file was using savedir(), which ignored eventual changes
+# in the current working directory and caused the malfunctioning.
+#
+# The problem was reported by Piotr Rotter on 2013-03-22.
+#
+# This testcase is based on scripts provided by Piotr Rotter and Nathan
+# Stratton Treadway.
+#
+# References: <514C8F56.90900@active24.pl>,
+#             http://lists.gnu.org/archive/html/bug-tar/2013-03/msg00036.html, 
+#             <20130326181922.GZ3732@shire.ontko.com>,
+#             http://lists.gnu.org/archive/html/bug-tar/2013-03/msg00042.html,
+#             <20130327051828.GA3732@shire.ontko.com>,
+#             http://lists.gnu.org/archive/html/bug-tar/2013-03/msg00043.html,
+#             <20130327054957.GB3732@shire.ontko.com>,
+#             http://lists.gnu.org/archive/html/bug-tar/2013-03/msg00044.html
+
+AT_TAR_CHECK([
+mkdir A
+echo 'a' > A/a
+echo 'a' > A/b
+
+decho C0
+tar -g test.snar -vcf test.0.tar A
+
+echo 'a' > A/c
+decho C1
+tar -g test.snar -vcf test.1.tar A
+
+rm -f A/a
+decho C2
+tar -g test.snar -vcf test.2.tar A
+
+mkdir ext
+rm -rf A
+
+decho E0
+tar -g test.snar -vxf test.0.tar -C ext/
+decho E1
+tar -g test.snar -vxf test.1.tar -C ext/
+
+mkdir ext/A/B
+touch ext/A/B/file
+
+decho E2
+tar -g test.snar -vxf test.2.tar -C ext/
+
+echo FIN
+test -d A && echo >&2 "toplevel A exists"
+exit 0
+],
+[0],
+[C0
+A/
+A/a
+A/b
+C1
+A/
+A/c
+C2
+A/
+E0
+A/
+A/a
+A/b
+E1
+A/
+A/c
+E2
+A/
+tar: Deleting 'A/a'
+tar: Deleting 'A/B'
+FIN
+],
+[C0
+tar: A: Directory is new
+C1
+C2
+E0
+E1
+E2
+],[],[],[gnu, oldgnu, posix])
+
+AT_CLEANUP

tests/testsuite.at

@@ -296,6 +296,7 @@ m4_include([incr03.at])
 m4_include([incr04.at])
 m4_include([incr05.at])
 m4_include([incr06.at])
+m4_include([incr07.at])
 
 AT_BANNER([Files removed while archiving])
 m4_include([filerem01.at])