It has been pointed out that the wording of the license of this library is
not entirely clear.
The term "dual licensing" usually refers to a licence choice of two
licenses "LICENSE1 _or_ LICENSE2.
Instead the license of this library claimed "LICENSE1 _and_ LICENSE2".
After an internal discussion with @metajack and @pasis it was made clear
that the initial idea was to dual license the library in the usual way.
This was also made clear by jack on the ML in the past [0].
As of jack, these licensing terms originated from jquery, which also used
the 'and' version in the past and has since been corrected [1].
This patch changes the license terms to 'MIT or GPLv3' and also adds SPDX
headers [2].
[0] https://groups.google.com/g/libstrophe/c/JkFgr601JQc
[1] https://stackoverflow.com/q/2758409
[2] https://spdx.org
Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>
Introduced UNUSED macro with cast to void in commoh.h for internal
use. Used cast to void directly in those files which do not
include common.h. Although this change doesn't fix semantic issues
with unused function parameters, it does explicitly mark all those
places, which might require attention in future.
@sjaeckel integrated clang-format with formal coding style. Run his
script and commit changes.
There are pros and cons of this commit.
Mixed coding style is a "broken window". A good single style simplifies
reading and writing code.
On the other hand, this is a big change which will lead to conflicts.
expat is still the default parser, but libxml2 can also be used
via an option to the configure script. New parsers can easily be
added by implementing a parser_foo.c that uses the interface defined
in parser.h.
