versioning: Make current configure.ac version available in CMakeLists.txt

[mrdeep1]

Create a CMakeLists.txt.in to contain latest versions, which then updates CMakeLists.txt with updated versions etc. which is then distributed.

CMake unfortunately does not handle, for example, 4.3.1rc1 (the rc1 suffix) for the "project (libcoap VERSION xxx)", so this has to end up as 4.3.1

[obgm]

CMake unfortunately does not handle, for example, 4.3.1rc1 (the rc1 suffix)

That is why I just ignored CMake.

[obgm]

The big step here is to automate the creation of CMakeLists.txt from configure.ac. Do we really want this?

[mrdeep1]

A good question, which is why I hesitated before doing this. We do this for all the coap_config.*.h files with the coap_config.*.h.in templates.

We could go through the manual process of updating the version strings and remove all the coap_config.*.h.in to be consistent here (but also need to watch updating things like 4003000 as well to 40030001).