various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

19 files changed, 38 insertions, 0 deletions

diff --git a/adduser/adduser.sh b/adduser/adduser.sh
index 4b0a6f6..5f80d77 100644
--- a/adduser/adduser.sh
+++ b/adduser/adduser.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 #
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
 # Copyright (c) 2002-2004 Michael Telahun Makonnen. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
diff --git a/adduser/rmuser.sh b/adduser/rmuser.sh
index 6b09225..abaf004 100644
--- a/adduser/rmuser.sh
+++ b/adduser/rmuser.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 #
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
 # Copyright (c) 2002, 2003 Michael Telahun Makonnen. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
diff --git a/pw/bitmap.c b/pw/bitmap.c
index 8e96bff..be82b2c 100644
--- a/pw/bitmap.c
+++ b/pw/bitmap.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/bitmap.h b/pw/bitmap.h
index 4d6cfe4..570c678 100644
--- a/pw/bitmap.h
+++ b/pw/bitmap.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/cpdir.c b/pw/cpdir.c
index 679758b..4e6ca88 100644
--- a/pw/cpdir.c
+++ b/pw/cpdir.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/grupd.c b/pw/grupd.c
index 5d0df02..e98dd29 100644
--- a/pw/grupd.c
+++ b/pw/grupd.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/psdate.c b/pw/psdate.c
index b63d882..94d2a34 100644
--- a/pw/psdate.c
+++ b/pw/psdate.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/psdate.h b/pw/psdate.h
index a1e99d4..bb71da3 100644
--- a/pw/psdate.h
+++ b/pw/psdate.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw.c b/pw/pw.c
index 700a7b2..5f02a15 100644
--- a/pw/pw.c
+++ b/pw/pw.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw.h b/pw/pw.h
index 592d592..816c755 100644
--- a/pw/pw.h
+++ b/pw/pw.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw_conf.c b/pw/pw_conf.c
index a3bd0bd..e1dc682 100644
--- a/pw/pw_conf.c
+++ b/pw/pw_conf.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw_group.c b/pw/pw_group.c
index 0a2b1eb..dd65062 100644
--- a/pw/pw_group.c
+++ b/pw/pw_group.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw_log.c b/pw/pw_log.c
index fe8d803..17e14d1 100644
--- a/pw/pw_log.c
+++ b/pw/pw_log.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw_nis.c b/pw/pw_nis.c
index 087c946..4b70bc1 100644
--- a/pw/pw_nis.c
+++ b/pw/pw_nis.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw_user.c b/pw/pw_user.c
index 92d5c6c..395564d 100644
--- a/pw/pw_user.c
+++ b/pw/pw_user.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pw_vpw.c b/pw/pw_vpw.c
index 58e5294..ea87f71 100644
--- a/pw/pw_vpw.c
+++ b/pw/pw_vpw.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pwupd.c b/pw/pwupd.c
index 87c3c99..ac91c9e 100644
--- a/pw/pwupd.c
+++ b/pw/pwupd.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/pwupd.h b/pw/pwupd.h
index daca487..b6f268b 100644
--- a/pw/pwupd.h
+++ b/pw/pwupd.h
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *
diff --git a/pw/rm_r.c b/pw/rm_r.c
index 45fc5d1..940266d 100644
--- a/pw/rm_r.c
+++ b/pw/rm_r.c
@@ -1,4 +1,6 @@
 /*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
  * Copyright (C) 1996
  *	David L. Nugent.  All rights reserved.
  *