man: change license of examples to MIT-0

Quoting Richard Fontana in [1]:

  CC0 has been listed by Fedora as a 'good' license for code and content
  (corresponding to allowed and allowed-content under the new system). We plan
  to classify CC0 as allowed-content only, so that CC0 would no longer be
  allowed for code.

  Over a long period of time a consensus has been building in FOSS that
  licenses that preclude any form of patent licensing or patent forbearance
  cannot be considered FOSS. CC0 has a clause that says: "No trademark or
  patent rights held by Affirmer are waived, abandoned, surrendered, licensed
  or otherwise affected by this document." (The trademark side of that clause
  is nonproblematic from a FOSS licensing norms standpoint.) The regular
  Creative Commons licenses have similar clauses.

For the case of our documentation snippets, patent issues do not matter much.
But it is always nicer to have a license that is considerred acceptable without
any further considerations. So let's change the license to the (now recommended
replacement) MIT-0.

[1] https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/NO7KGDNL5GX3KCB7T3XTGFA3QPSUJA6R/

Using 'git blame -b' and 'git log -p --follow', I identified the following
folks as having made non-trivial changes to those snippets:

  Lennart Poettering
  Tom Gundersen
  Luca Bocassi
  Zbigniew Jędrzejewski-Szmek
  Thomas Mühlbacher
  Daan De Meyer

I'll ask for confirmation in the pull request.

LICENSES/README.md

@@ -47,8 +47,9 @@ The following exceptions apply:
    - src/basic/siphash24.h
    - src/systemctl/systemd-sysv-install.SKELETON
    - tools/check-includes.pl
-   - all examples under man/
    - config files and examples under /network
+  * the following sources are licensed under the **MIT-0** license:
+   - all examples under man/
  * the following sources are under **Public Domain** (LicenseRef-murmurhash2-public-domain):
    - src/basic/MurmurHash2.c
    - src/basic/MurmurHash2.h

man/50-xdg-data-dirs.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 # set the default value
 XDG_DATA_DIRS="${XDG_DATA_DIRS:-/usr/local/share/:/usr/share}"

man/90-rearrange-path.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 """
 

man/check-os-release-simple.py

@@ -1,5 +1,5 @@
 #!/usr/bin/python
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 import platform
 os_release = platform.freedesktop_os_release()

man/check-os-release.py

@@ -1,5 +1,5 @@
 #!/usr/bin/python
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 import ast
 import re

man/check-os-release.sh

@@ -1,5 +1,5 @@
 #!/bin/sh -eu
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 test -e /etc/os-release && os_release='/etc/os-release' || os_release='/usr/lib/os-release'
 . "${os_release}"

man/event-quick-child.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <assert.h>
 #include <stdio.h>

man/fido2-crypttab.sh

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 # Enroll the security token in the LUKS2 volume. Replace /dev/sdXn by the
 # partition to use (e.g. /dev/sda1).

man/glib-event-glue.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <stdlib.h>
 #include <glib.h>

man/hwdb-usb-device.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <stdio.h>
 #include <stdint.h>

man/id128-app-specific.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <stdio.h>
 #include <systemd/sd-id128.h>

man/inotify-watch-tmp.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <stdio.h>
 #include <string.h>

man/journal-enumerate-fields.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <stdio.h>

man/journal-iterate-foreach.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <stdio.h>

man/journal-iterate-poll.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <poll.h>
 #include <time.h>

man/journal-iterate-unique.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <stdio.h>

man/journal-iterate-wait.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <stdio.h>

man/journal-stream-fd.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <syslog.h>

man/path-documents.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <stdio.h>
 #include <stdlib.h>

man/print-unit-path.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <stdio.h>

man/sd-bus-container-append.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <systemd/sd-bus.h>
 

man/sd-bus-container-read.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <stdio.h>
 

man/sd_bus_error-example.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <string.h>

man/send-unit-files-changed.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <systemd/sd-bus.h>
 #define _cleanup_(f) __attribute__((cleanup(f)))

man/tpm2-crypttab.sh

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 # Enroll the TPM2 security chip in the LUKS2 volume, and bind it to PCR 7
 # only. Replace /dev/sdXn by the partition to use (e.g. /dev/sda1).

man/vtable-example.c

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: CC0-1.0 */
+/* SPDX-License-Identifier: MIT-0 */
 
 #include <errno.h>
 #include <stdbool.h>

man/yubikey-crypttab.sh

@@ -1,4 +1,4 @@
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT-0
 
 # Destroy any old key on the Yubikey (careful!)
 ykman piv reset