Centralize variable substitution

A bunch of places need to edit files to incorporate the configured paths
i.e. bindir, sbindir etc. Move this logic into a common file.

Create arc_summary by copying arc_summary[23] as appropriate at build
time instead of install time.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10559

udev/rules.d/Makefile.am

@@ -1,19 +1,8 @@
+include $(top_srcdir)/config/Substfiles.am
+
 udevrule_DATA = \
 	69-vdev.rules \
 	60-zvol.rules \
 	90-zfs.rules
 
-EXTRA_DIST = \
-	69-vdev.rules.in \
-	60-zvol.rules.in \
-	90-zfs.rules.in
-
-$(udevrule_DATA):%:%.in
-	-$(SED) -e 's,@bindir\@,$(bindir),g' \
-		-e 's,@sbindir\@,$(sbindir),g' \
-		-e 's,@udevdir\@,$(udevdir),g' \
-		-e 's,@udevruledir\@,$(udevruledir),g' \
-		-e 's,@sysconfdir\@,$(sysconfdir),g' \
-		$< > '$@'
-
-CLEANFILES = $(udevrule_DATA)
+SUBSTFILES += $(udevrule_DATA)