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.
nspawn: fix two typos in error messages On errors, mention the functions that really failed.
util-lib: split out allocation calls into alloc-util.[ch]
util-lib: split out user/group/uid/gid calls into user-util.[ch]
util-lib: split out fd-related operations into fd-util.[ch] There are more than enough to deserve their own .c file, hence move them over.
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.
nspawn: remove nspawn.h, it's empty now
nspawn: split out --uid= logic into nspawn-setuid.[ch]