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.

install: when exporting prefix InstallInfo to become UnitFileInstallInfo All other types exported from install.h should be namespaces like this, hence namespace InstallInfo the same way. Also, remove external forward definition of UnitFileScope type.

specifier: rework specifier calls to return proper error message Previously the specifier calls could only indicate OOM by returning NULL. With this change they will return negative errno-style error codes like everything else.

install: allow specifiers in WantedBy/RequiredBy/Alias This allows one templated unit to refer to another templated unit at installation time. Examples: > grep WantedBy ~/.config/systemd/user/mpop@.timer WantedBy=services@%i.target > srv disable mpop@iit.timer rm '/home/alxchk/.config/systemd/user/services@iit.target.wants/mpop@iit.timer' > srv enable mpop@iit.timer ln -s '/home/alxchk/.config/systemd/user/mpop@.timer' '/home/alxchk/.config/systemd/user/services@iit.target.wants/mpop@iit.timer' Based-on-patch-by: Oleksii Shevchuk <alxchk@gmail.com>