sd-dlopen: relicense header to MIT-0

Relicense sd-dlopen.h from LGPL-2.1-or-later to MIT-0 so that
downstream projects can copy/paste the macros directly without
introducing a build dependency on the systemd headers.

Acked-by: Lennart Poettering <lennart@amutable.com>
Acked-by: Luca Boccassi <luca.boccassi@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

LICENSES/README.md

@@ -57,6 +57,7 @@ The following exceptions apply:
  * the following sources are licensed under the **MIT-0** license:
    - all examples under man/
    - config files and examples under /network
+   - src/systemd/sd-dlopen.h
  * the following sources are under **Public Domain** (LicenseRef-murmurhash2-public-domain):
    - src/basic/MurmurHash2.c
    - src/basic/MurmurHash2.h

src/systemd/sd-dlopen.h

@@ -1,20 +1,24 @@
-/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/* SPDX-License-Identifier: MIT-0 */
 #ifndef foosddlopenhfoo
 #define foosddlopenhfoo
 
 /***
-  systemd is free software; you can redistribute it and/or modify it
-  under the terms of the GNU Lesser General Public License as published by
-  the Free Software Foundation; either version 2.1 of the License, or
-  (at your option) any later version.
+  Copyright © 2026 The systemd Project
 
-  systemd 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
-  Lesser General Public License for more details.
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so.
 
-  You should have received a copy of the GNU Lesser General Public License
-  along with systemd; If not, see <https://www.gnu.org/licenses/>.
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
 ***/
 
 #include <stdint.h>