... as requested in
https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/DJ7HDNRM5JGBSA4HL3UWW5ZGLQDJ6Y7M/.
Adding the macro makes it marginally easier to create generators
for outside projects.
I opted for "generatordir" and "usergeneratordir" to match
%unitdir and %userunitdir. OTOH, "_systemd" prefix makes it obvious
that this is related to systemd. "%_generatordir" would be to generic
of a name.
%_sysusersdir @sysusersdir@
%_sysctldir @sysctldir@
%_binfmtdir @binfmtdir@
+%_systemdgeneratordir @systemgeneratordir@
+%_systemdusergeneratordir @usergeneratordir@
%systemd_requires \
Requires(post): systemd \