Avoid cygwin 1.7 crash with closed stdout.

* gnulib: Update.
* doc/m4.texinfo (Command line files): Add test; regression
introduced 2008-07-17.
* NEWS: Document the change.

Signed-off-by: Eric Blake <ebb9@byu.net>

4 files changed, 22 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 3bfa1363..ea2a8794 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2009-07-20  Eric Blake  <ebb9@byu.net>
 
+	Avoid cygwin 1.7 crash with closed stdout.
+	* gnulib: Update.
+	* doc/m4.texinfo (Command line files): Add test; regression
+	introduced 2008-07-17.
+	* NEWS: Document the change.
+
 	A status of 127 does not always imply esyscmd failure.
 	* src/builtin.c (m4_esyscmd): Silence gnulib message; regression
 	introduced 2009-03-05.
diff --git a/NEWS b/NEWS
index 485a143c..f3f65d42 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,9 @@ Software Foundation, Inc.
 * Noteworthy changes in Version 1.4.14 (2009-??-??) [stable]
   Released by Eric Blake, based on git version 1.4.13.*
 
+** Fix regression introduced in 1.4.12 where executing with stdout closed
+   could crash m4 on exit on some platforms.
+
 ** Fix regression introduced in 1.4.13 in the `esyscmd' builtin, where
    a child status of 127 made m4 print a spurious message to stderr.
 
diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index eb76109e..6c03ce70 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -960,6 +960,19 @@ options.
 @example
 @error{}m4: cannot open `Makefile/': Not a directory
 @end example
+
+@comment Test that closed stderr does not cause a crash.
+
+@example
+ifdef(`__unix__', ,
+      `errprint(` skipping: syscmd does not have unix semantics
+')m4exit(`77')')dnl
+changequote(`[', `]')dnl
+syscmd([echo | ']__program__[' >&-])dnl
+@error{}m4: write error: Bad file descriptor
+sysval
+@result{}1
+@end example
 @end ignore
 
 @node Syntax
diff --git a/gnulib b/gnulib
-Subproject e3e47d1710f6154c54b65c5d9dd5d56516a893d
+Subproject d19ab0454ad81cd702f17864f082aefcbea6687