pkg-config: export systemd{system,user}generatordir and catalogdir

We export the location of a bunch of directories this way,
so it makes sense to add those three. Especially catalogdir
is something that we want people to add things to.

Note on the naming: the first two are tied closely to systemd
itself, so I prefixed them with "systemd". The third one is
rather more generic, so no prefix.

https://bugs.freedesktop.org/show_bug.cgi?id=67635

Makefile.am

@@ -82,9 +82,9 @@ userunitdir=$(prefix)/lib/systemd/user
 userpresetdir=$(prefix)/lib/systemd/user-preset
 tmpfilesdir=$(prefix)/lib/tmpfiles.d
 sysctldir=$(prefix)/lib/sysctl.d
-usergeneratordir=$(prefix)/lib/systemd/user-generators
 pkgincludedir=$(includedir)/systemd
 systemgeneratordir=$(rootlibexecdir)/system-generators
+usergeneratordir=$(prefix)/lib/systemd/user-generators
 systemshutdowndir=$(rootlibexecdir)/system-shutdown
 systemsleepdir=$(rootlibexecdir)/system-sleep
 systemunitdir=$(rootprefix)/lib/systemd/system
@@ -4106,6 +4106,8 @@ substitutions = \
        '|catalogdir=$(catalogdir)|' \
        '|tmpfilesdir=$(tmpfilesdir)|' \
        '|sysctldir=$(sysctldir)|' \
+       '|systemgeneratordir=$(systemgeneratordir)|' \
+       '|usergeneratordir=$(usergeneratordir)|' \
        '|PACKAGE_VERSION=$(PACKAGE_VERSION)|' \
        '|PACKAGE_NAME=$(PACKAGE_NAME)|' \
        '|PACKAGE_URL=$(PACKAGE_URL)|' \

src/core/systemd.pc.in

@@ -16,6 +16,9 @@ systemdsystemconfdir=@pkgsysconfdir@/system
 systemduserconfdir=@pkgsysconfdir@/user
 systemdsystemunitpath=${systemdsystemconfdir}:/etc/systemd/system:/run/systemd/system:/usr/local/lib/systemd/system:${systemdsystemunitdir}:/usr/lib/systemd/system:/lib/systemd/system
 systemduserunitpath=${systemduserconfdir}:/etc/systemd/user:/run/systemd/user:/usr/local/lib/systemd/user:/usr/local/share/systemd/user:${systemduserunitdir}:/usr/lib/systemd/user:/usr/share/systemd/user
+systemdsystemgeneratordir=@systemgeneratordir@
+systemdusergeneratordir=@usergeneratordir@
+catalogdir=@catalogdir@
 
 Name: systemd
 Description: systemd System and Service Manager