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names and years are hard to maintain and often out-of-date or plain wrong.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.
Convert several preformatted code block literals that enumerate lists of
options or variables to use reST definition lists instead. Manually
wrap other long lines in code blocks.
Fixes issues #14812 and #14813 where find_package(OpenMP QUIET) and
find_package(Qt4 QUIET) would still print out messages when calling
check*() functions.
Also a partial fix for #14445 where building CMake
(without cmake-gui) when Qt5 is installed and Qt4 is not installed
and warnings come out of FindQt4.cmake.
It designed to search for implementation of backtrace(3) routine.
Currently it is used in OpenBSD Ports for building Clementine
music player.
A lot of input from brad.king@ and neundorf@.