selinux: split up mac_selinux_have() from mac_selinux_use() Let's distuingish the cases where our code takes an active role in selinux management, or just passively reports whatever selinux properties are set. mac_selinux_have() now checks whether selinux is around for the passive stuff, and mac_selinux_use() for the active stuff. The latter checks the former, plus also checks UID == 0, under the assumption that only when we run priviliged selinux management really makes sense. Fixes: #1941

util-lib: split out allocation calls into alloc-util.[ch]

src/basic: rename audit.[ch] → audit-util.[ch] and capability.[ch] → capability-util.[ch] The files are named too generically, so that they might conflict with the upstream project headers. Hence, let's add a "-util" suffix, to clarify that this are just our utility headers and not any official upstream headers.

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: split all hostname related calls into hostname-util.c

test-condition: add more test cases

shared: rename condition-util.[ch] to condition.[ch] Now that we only have one file with condition implementations around, we can drop the -util suffix and simplify things a bit.