campaignd: Emit debug messages when writing configuration to disk
campaignd: Write config to disk even if the clock is running backwards
campaignd: Use a POSIX monotonic clock for scheduling config commits

Only available on Linux and probably some BSD systems. For other systems
we issue a #warning and use time() instead (which will cause the
compiler to quit with -Werror, but that's the whole point).
fixup cmakelists, they weren't adding the new libraries
fixup missing includes in X11 clipboard code

This was broken for homebrew it seems by not having the includes.
Fix thread count setting for 1.9 wesnothd and add one for 1.12
create_symlinks: Make an exception for 1.10
remove unused attributes from carryover sides
add a comment
remove unused function