Require that "(exit $fail); exit $fail" be last line of each test.

* maint.mk (sc_require_test_exit_idiom): New rule to enforce policy.
* tests/cp/acl: Adhere to the new policy.
* tests/cp/preserve-gid: Likewise.
* tests/dd/misc:
* tests/install/create-leading:
* tests/ln/sf-1:
* tests/ls/symlink-slash:
* tests/misc/help-version:
* tests/misc/ls-time:
* tests/misc/nice:
* tests/misc/shred-remove:
* tests/misc/stty:
* tests/misc/stty-row-col:
* tests/mkdir/p-1:
* tests/mkdir/p-2:
* tests/mkdir/p-3:
* tests/mkdir/p-v:
* tests/mkdir/special-1:
* tests/mkdir/writable-under-readonly:
* tests/mv/acl:
* tests/mv/backup-is-src:
* tests/mv/diag:
* tests/mv/dir-file:
* tests/mv/force:
* tests/mv/hard-link-1:
* tests/mv/i-2:
* tests/mv/i-4:
* tests/mv/into-self:
* tests/mv/into-self-2:
* tests/mv/into-self-3:
* tests/mv/partition-perm:
* tests/mv/to-symlink:
* tests/rmdir/ignore:
* tests/tail-2/assert:
* tests/tail-2/assert-2:
* tests/touch/dangling-symlink:
* tests/touch/dir-1:
* tests/touch/empty-file:
* tests/touch/fifo:
* tests/touch/no-rights: Likewise.

Signed-off-by: Jim Meyering <meyering@redhat.com>

tests/touch/dangling-symlink

@@ -2,7 +2,7 @@
 # Make sure touch can create a file through a dangling symlink.
 # This was broken in the 4.0[e-i] test releases.
 
-# Copyright (C) 1999, 2000, 2007 Free Software Foundation, Inc.
+# Copyright (C) 1999, 2000, 2007-2008 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -51,4 +51,4 @@ when operating on dangling symlinks.
   esac
 fi
 
-exit $fail
+(exit $fail); exit $fail

tests/touch/dir-1

@@ -11,4 +11,4 @@ fi
 
 fail=0
 touch . || fail=1
-exit $fail
+(exit $fail); exit $fail

tests/touch/empty-file

@@ -1,7 +1,7 @@
 #!/bin/sh
 # Make sure touch can set the mtime on an empty file.
 
-# Copyright (C) 1998, 1999, 2000, 2005-2007 Free Software Foundation, Inc.
+# Copyright (C) 1998, 1999, 2000, 2005-2008 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -82,4 +82,4 @@ if test $fail != 0; then
 EOF
 fi
 
-exit $fail
+(exit $fail); exit $fail

tests/touch/fifo

@@ -1,7 +1,7 @@
 #!/bin/sh
 # Make sure touch works on fifos without hanging.
 
-# Copyright (C) 2000, 2007 Free Software Foundation, Inc.
+# Copyright (C) 2000, 2007-2008 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -35,4 +35,4 @@ fail=0
 
 touch fifo || fail=1
 
-exit $fail
+(exit $fail); exit $fail

tests/touch/no-rights

@@ -2,7 +2,7 @@
 # Make sure touch can update the times on a file that is neither
 # readable nor writable.
 
-# Copyright (C) 1999, 2000, 2002, 2006-2007 Free Software Foundation, Inc.
+# Copyright (C) 1999, 2000, 2002, 2006-2008 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -42,4 +42,4 @@ test "$*" = "x t1 t2" || fail=1
 # Also test the combination of --no-create and -a.
 touch -a --no-create t1 || fail=1
 
-exit $fail
+(exit $fail); exit $fail