tree-wide: remove Emacs lines from all files This should be handled fine now by .dir-locals.el, so need to carry that stuff in every file.

udev: add emacs header line Otherwise emacs wants to use 2-space indentation and other attrocities.

util-lib: split our string related calls from util.[ch] into its own file string-util.[ch] There are more than enough calls doing string manipulations to deserve its own files, hence do something about it. This patch also sorts the #include blocks of all files that needed to be updated, according to the sorting suggestions from CODING_STYLE. Since pretty much every file needs our string manipulation functions this effectively means that most files have sorted #include blocks now. Also touches a few unrelated include files.

util: rework strappenda(), and rename it strjoina() After all it is now much more like strjoin() than strappend(). At the same time, add support for NULL sentinels, even if they are normally not necessary.

udevadm: split out find_device helper The idea is to unify the way that devices can be specified.