add some copyright headers

[Bruno Haible]

Ineiev is making pressure to add copyright headers and license notices, as
mandated by the GNU Maintainers Guide [1][2], to various packages. In
particular for GNU gettext, I wrote a script to make sure that I don't
put files into the tarball that he would need to complain about.

Now that I'm requesting more modules from gnulib, this script says: 

*** Missing copyright header in file gettext-tools/gnulib-lib/file-set.h
*** Missing copyright header in file gettext-tools/gnulib-lib/hash-triple.h

These files are 15 and 24 lines long, respectively. Per [1], they are
"nontrivial" and thus should carry a copyright header and license notice.

Let me add such a header to all the files in lib/ with 10 or more lines:

     46 se-context.in.h
     24 hash-triple.h
     16 fchown-stub.c
     15 file-set.h
     14 stdopen.h
     13 mkancesdirs.h
     13 dev-ino.h
     12 ino-map.h
     12 di-set.h
     11 scratch_buffer.h
     11 idcache.h
     10 userspec.h

[1] https://www.gnu.org/prep/maintain/html_node/Copyright-Notices.html
[2] https://www.gnu.org/prep/maintain/html_node/License-Notices.html


2020-07-05  Bruno Haible  <bruno@clisp.org>

        Add some copyright headers.
        * lib/dev-ino.h: Add copyright header.
        * lib/di-set.h: Likewise.
        * lib/fchown-stub.c: Likewise.
        * lib/file-set.h: Likewise.
        * lib/hash-triple.h: Likewise.
        * lib/idcache.h: Likewise.
        * lib/ino-map.h: Likewise.
        * lib/mkancesdirs.h: Likewise.
        * lib/scratch_buffer.h: Likewise.
        * lib/se-context.in.h: Likewise.
        * lib/stdopen.h: Likewise.
        * lib/userspec.h: Likewise.

diff --git a/lib/dev-ino.h b/lib/dev-ino.h
index 695d38c..7b62d48 100644
--- a/lib/dev-ino.h
+++ b/lib/dev-ino.h
@@ -1,3 +1,21 @@
+/* A simple (device, inode) struct.
+   Copyright (C) 2003-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2003.  */
+
 #ifndef DEV_INO_H
 # define DEV_INO_H 1
 
diff --git a/lib/di-set.h b/lib/di-set.h
index bec5b3f..743bc7d 100644
--- a/lib/di-set.h
+++ b/lib/di-set.h
@@ -1,3 +1,21 @@
+/* Manipulate sets of device-inode pairs efficiently.
+   Copyright (C) 2010-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2010.  */
+
 #ifndef _GL_DI_SET_H
 # define _GL_DI_SET_H
 
diff --git a/lib/fchown-stub.c b/lib/fchown-stub.c
index 62b6969..65be66e 100644
--- a/lib/fchown-stub.c
+++ b/lib/fchown-stub.c
@@ -1,3 +1,21 @@
+/* Change ownership of a file.
+   Copyright (C) 2004-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert, 2004.  */
+
 #include <config.h>
 
 #include <sys/types.h>
diff --git a/lib/file-set.h b/lib/file-set.h
index 4e47d95..244951f 100644
--- a/lib/file-set.h
+++ b/lib/file-set.h
@@ -1,3 +1,21 @@
+/* Very specialized set-of-files code.
+   Copyright (C) 2007-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2007.  */
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <stdbool.h>
diff --git a/lib/hash-triple.h b/lib/hash-triple.h
index 0658d81..c65450e 100644
--- a/lib/hash-triple.h
+++ b/lib/hash-triple.h
@@ -1,3 +1,21 @@
+/* Hash functions for file-related (name, device, inode) triples.
+   Copyright (C) 2007-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2007.  */
+
 #ifndef HASH_TRIPLE_H
 #define HASH_TRIPLE_H
 
diff --git a/lib/idcache.h b/lib/idcache.h
index e7573b8..012c792 100644
--- a/lib/idcache.h
+++ b/lib/idcache.h
@@ -1,3 +1,21 @@
+/* Username <--> uid and groupname <--> gid conversions, with cache for speed.
+   Copyright (C) 2007-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2007.  */
+
 #ifndef IDCACHE_H
 # define IDCACHE_H 1
 
diff --git a/lib/ino-map.h b/lib/ino-map.h
index 1bdf886..9f7d5e8 100644
--- a/lib/ino-map.h
+++ b/lib/ino-map.h
@@ -1,3 +1,21 @@
+/* Maintain a mapping of ino_t numbers to small integers.
+   Copyright (C) 2010-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert, 2010.  */
+
 #ifndef _GL_INO_MAP_H
 # define _GL_INO_MAP_H
 
diff --git a/lib/mkancesdirs.h b/lib/mkancesdirs.h
index fdfd654..6a9d1e0 100644
--- a/lib/mkancesdirs.h
+++ b/lib/mkancesdirs.h
@@ -1,3 +1,21 @@
+/* Ensure the existence of the ancestor directories of a file.
+   Copyright (C) 2006-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert, 2006.  */
+
 #include <stddef.h>
 
 #ifdef __cplusplus
diff --git a/lib/scratch_buffer.h b/lib/scratch_buffer.h
index 4c0db3e..0b45f92 100644
--- a/lib/scratch_buffer.h
+++ b/lib/scratch_buffer.h
@@ -1,3 +1,21 @@
+/* Variable-sized buffer with on-stack default allocation.
+   Copyright (C) 2017-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert, 2017.  */
+
 #ifndef _GL_SCRATCH_BUFFER_H
 #define _GL_SCRATCH_BUFFER_H
 
diff --git a/lib/se-context.in.h b/lib/se-context.in.h
index c3890a2..5306937 100644
--- a/lib/se-context.in.h
+++ b/lib/se-context.in.h
@@ -1,3 +1,21 @@
+/* SELinux-related headers.
+   Copyright (C) 2007-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2007.  */
+
 #ifndef SELINUX_CONTEXT_H
 # define SELINUX_CONTEXT_H
 
diff --git a/lib/stdopen.h b/lib/stdopen.h
index 27901d3..ccc62a0 100644
--- a/lib/stdopen.h
+++ b/lib/stdopen.h
@@ -1,3 +1,21 @@
+/* Arrange for stdin/stdout/stderr to be open.
+   Copyright (C) 2005-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2005.  */
+
 #ifndef STDOPEN_H
 # define STDOPEN_H 1
 
diff --git a/lib/userspec.h b/lib/userspec.h
index 67af845..e20c390 100644
--- a/lib/userspec.h
+++ b/lib/userspec.h
@@ -1,3 +1,21 @@
+/* Parse a 'user:group' specifier (e.g. the first argument of chown utility).
+   Copyright (C) 2003-2020 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering, 2003.  */
+
 #ifndef USERSPEC_H
 # define USERSPEC_H 1