This rewrites the version info using lokid's approach of compiling it
into a .cpp file that gets generated as part of the build (*not* during
the configure stage).
Among other things, this means that changing the version no longer
invalidates ccache or cmake dependencies, and because it depends on
`.git/index` git commits will cause the version to be regenerated,
making the commit tag more reliable (currently if you rebuild without
running cmake your git commit tag doesn't update).
had an epiphany earlier
i kept having problems with static linking because
i merged the GNU C runtime with the SEH library
instead of merging the latter with pthread
* Import cxxopts to replace getopts usage
* Add visual studio build things
* Fixup abseil build parts
* Replace __attribute__((unused)) with ABSL_ATTRIBUTE_UNUSED
* Fixup minor windows build issues
* Replace getopts usage
* Temporarily fixup .rc files
* More minor windows fixes
* Get a working build
* Revert .rc files
* Revert changes to nodedb
