Do not hardcode paths in scripts

Try to reuse the configured paths as much as possible. Unfortunately, to
be able to fully expand some variable (e.g. `bindir`), these files must
be expanded by make, not by configure. This adds some complexity:

https://www.gnu.org/software/automake/manual/html_node/Scripts.html

configure.ac

@@ -1149,8 +1149,6 @@ AC_CONFIG_FILES([
         master/Kbuild
         master/Makefile
         script/Makefile
-        script/ethercat.service
-        script/ethercatctl
         script/init.d/Makefile
         script/init.d/ethercat
         script/sysconfig/Makefile

script/Makefile.am

@@ -37,13 +37,34 @@ sbin_SCRIPTS = ethercatctl
 
 dist_sysconf_DATA = ethercat.conf
 
-EXTRA_DIST = \
+script_templates = \
 	ethercatctl.in \
-	ethercat.service.in \
+	ethercat.service.in
+
+EXTRA_DIST = \
+	$(script_templates) \
 	ifup-eoe.sh
 
+CLEANFILES = \
+	ethercatctl \
+	ethercat.service
+
 if HAVE_SYSTEMD
 systemdsystemunit_DATA = ethercat.service
 endif
 
+
+# Any precious variable used inside script_templates should appear here
+expand_script = $(SED) \
+	-e 's,[@]VERSION[@],$(VERSION),g' \
+	-e 's,[@]bindir[@],$(bindir),g' \
+	-e 's,[@]sbindir[@],$(sbindir),g' \
+	-e 's,[@]sysconfdir[@],$(sysconfdir),g'
+
+ethercatctl: $(srcdir)/ethercatctl.in Makefile
+	$(expand_script) < $< > $@
+
+ethercat.service: $(srcdir)/ethercat.service.in Makefile
+	$(expand_script) < $< > $@
+
 #------------------------------------------------------------------------------

script/ethercat.service.in

@@ -22,8 +22,8 @@ Description=EtherCAT Master Kernel Modules
 [Service]
 Type=oneshot
 RemainAfterExit=yes
-ExecStart=@prefix@/sbin/ethercatctl start
-ExecStop=@prefix@/sbin/ethercatctl stop
+ExecStart=@sbindir@/ethercatctl start
+ExecStop=@sbindir@/ethercatctl stop
 
 [Install]
 WantedBy=multi-user.target

script/ethercatctl.in

@@ -38,11 +38,11 @@ MODPROBE=/sbin/modprobe
 RMMOD=/sbin/rmmod
 MODINFO=/sbin/modinfo
 
-ETHERCAT=@prefix@/bin/ethercat
+ETHERCAT=@bindir@/ethercat
 
 #------------------------------------------------------------------------------
 
-ETHERCAT_CONFIG=/etc/ethercat.conf
+ETHERCAT_CONFIG=@sysconfdir@/ethercat.conf
 
 if [ ! -r ${ETHERCAT_CONFIG} ]; then
     echo ${ETHERCAT_CONFIG} not existing;