build: Fix a check-copyright-headers failure.

* gettext-tools/libgettextpo/multithread-safe.txt: Add a license header.

diff --git a/gettext-tools/libgettextpo/multithread-safe.txt b/gettext-tools/libgettextpo/multithread-safe.txt
index af4d89e463a9b1219f10a31c9d1286a8a96ecf82..b7ee3dfd01eb7bc3413a86626be4437e1bc6a643 100644 (file)
--- a/gettext-tools/libgettextpo/multithread-safe.txt
+++ b/gettext-tools/libgettextpo/multithread-safe.txt
@@ -1,6 +1,8 @@
 This file explains in detail how we come to the conclusion that libgettextpo
 is multithread-safe.
 
+This file is in the public domain.
+
 2024-08: This is the list of all variables
   $ nm $file | grep ' [bBdD] '
 and their resolution.