Don't prevent random file systems from being unmounted.

This fix relies on having the 'fchdir' function, and on having
"." be searchable (or at least readable, on platforms lacking O_SEARCH),
but that's good enough to handle the vast majority of cases and the
remaining folks can just live with the annoyance of file systems
that occasionally can't be unmounted.
* configure.ac (fchdir): New function to check for.
* lib/save-cwd.c: Copy from gnulib, except omit the part that
allocates memory, since that can cause problems in Emacs.
* lib/save-cwd.h: Copy from gnulib.

Fixes: debbugs:18232

1 files changed, 13 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index cdf4152bc0a..6864b7043e1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2014-08-10  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Don't prevent random file systems from being unmounted (Bug#18232).
+        This fix relies on having the 'fchdir' function, and on having
+        "." be searchable (or at least readable, on platforms lacking O_SEARCH),
+        but that's good enough to handle the vast majority of cases and the
+        remaining folks can just live with the annoyance of file systems
+        that occasionally can't be unmounted.
+        * configure.ac (fchdir): New function to check for.
+        * lib/save-cwd.c: Copy from gnulib, except omit the part that
+        allocates memory, since that can cause problems in Emacs.
+        * lib/save-cwd.h: Copy from gnulib.
+
 2014-07-11  Paul Eggert  <eggert@cs.ucla.edu>
 
         * Makefile.in (install-arch-indep): Avoid readdir race (Bug#17971).