Simplify CMake per-source license notices

Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool.  Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience.  Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.

Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices.  It also references version control
history for more precise information.  Therefore we no longer need to spell
out the list of Contributors in each source file notice.

Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing".  The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.

Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically.  Manually fix up shebang lines and trailing
newlines in a few files.  Manually update the notices in a few files that the
script does not handle.

1 files changed, 3 insertions, 13 deletions

diff --git a/Modules/ExternalData.cmake b/Modules/ExternalData.cmake
index e7f8408..b00de14 100644
--- a/Modules/ExternalData.cmake
+++ b/Modules/ExternalData.cmake
@@ -1,3 +1,6 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
 #[=======================================================================[.rst:
 ExternalData
 ------------
@@ -316,19 +319,6 @@ file or set a variable:
 
 #]=======================================================================]
 
-#=============================================================================
-# Copyright 2010-2015 Kitware, Inc.
-#
-# Distributed under the OSI-approved BSD License (the "License");
-# see accompanying file Copyright.txt for details.
-#
-# This software is distributed WITHOUT ANY WARRANTY; without even the
-# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
-# See the License for more information.
-#=============================================================================
-# (To distribute this file outside of CMake, substitute the full
-#  License text for the above reference.)
-
 function(ExternalData_add_test target)
   # Expand all arguments as a single string to preserve escaped semicolons.
   ExternalData_expand_arguments("${target}" testArgs "${ARGN}")