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

tests/test-runner/bin/.gitignore

@@ -0,0 +1,2 @@
+test-runner.py
+zts-report.py

tests/test-runner/bin/Makefile.am

@@ -1,15 +1,8 @@
+include $(top_srcdir)/config/Substfiles.am
+
 pkgdatadir = $(datadir)/@PACKAGE@/test-runner/bin
-dist_pkgdata_SCRIPTS = \
+pkgdata_SCRIPTS = \
 	test-runner.py \
 	zts-report.py
-#
-# These scripts are compatible with both Python 2.6 and 3.4.  As such the
-# python 3 shebang can be replaced at install time when targeting a python
-# 2 system.  This allows us to maintain a single version of the source.
-#
-if USING_PYTHON_2
-install-data-hook:
-	$(SED) ${ac_inplace} -e 's|^#!/usr/bin/env python3|#!/usr/bin/env python2|' \
-	    $(DESTDIR)$(pkgdatadir)/test-runner.py \
-	    $(DESTDIR)$(pkgdatadir)/zts-report.py
-endif
+
+SUBSTFILES += $(pkgdata_SCRIPTS)

tests/test-runner/bin/test-runner.py.in

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env @PYTHON_SHEBANG@
 
 #
 # This file and its contents are supplied under the terms of the

tests/test-runner/bin/zts-report.py.in

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env @PYTHON_SHEBANG@
 
 #
 # This file and its contents are supplied under the terms of the
@@ -205,7 +205,6 @@ maybe = {
     'cli_root/zpool_import/zpool_import_missing_003_pos': ['SKIP', '6839'],
     'cli_root/zpool_trim/setup': ['SKIP', trim_reason],
     'cli_root/zpool_upgrade/zpool_upgrade_004_pos': ['FAIL', '6141'],
-    'cli_user/misc/arc_summary3_001_pos': ['SKIP', python_reason],
     'delegate/setup': ['SKIP', exec_reason],
     'history/history_004_pos': ['FAIL', '7026'],
     'history/history_005_neg': ['FAIL', '6680'],