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

cmd/arc_summary/.gitignore

@@ -0,0 +1 @@
+arc_summary

cmd/arc_summary/Makefile.am

@@ -1,4 +1,7 @@
-transform = $(program_transform_name)
+bin_SCRIPTS = arc_summary
+
+CLEANFILES = arc_summary
+EXTRA_DIST = arc_summary2 arc_summary3
 
 if USING_PYTHON_2
 SCRIPT = arc_summary2
@@ -6,9 +9,5 @@ else
 SCRIPT = arc_summary3
 endif
 
-dist_bin_SCRIPTS = $(SCRIPT)
-
-install-exec-hook:
-	before=$$(echo $(SCRIPT) | sed '$(transform)'); \
-	after=$$(echo arc_summary | sed '$(transform)'); \
-	mv "$(DESTDIR)$(bindir)/$$before" "$(DESTDIR)$(bindir)/$$after"
+arc_summary: $(SCRIPT)
+	cp $< $@