* tests/run_make_tests.pl: Preserve $make_command

* tests/scripts/options/dash-n: Use $make_command.  This fixes
a spurious failure when running tests with valgrind enabled.
diff --git a/tests/run_make_tests.pl b/tests/run_make_tests.pl
index ff10c21..7005f10 100644
--- a/tests/run_make_tests.pl
+++ b/tests/run_make_tests.pl
@@ -465,6 +465,8 @@
 
    # Set up for valgrind, if requested.
 
+   $make_command = $make_path;
+
    if ($valgrind) {
      my $args = $valgrind_args;
      open(VALGRIND, "> valgrind.out")
diff --git a/tests/scripts/options/dash-n b/tests/scripts/options/dash-n
index dfed419..02ae4a9 100644
--- a/tests/scripts/options/dash-n
+++ b/tests/scripts/options/dash-n
@@ -92,7 +92,7 @@
 close(MAKEFILE);
 
 &run_make_with_options($topmake, '-n --no-print-directory', &get_logfile);
-$answer = "$make_path -f \"$submake\" bar\ntouch inc\necho n --no-print-directory\n";
+$answer = "$make_command -f \"$submake\" bar\ntouch inc\necho n --no-print-directory\n";
 &compare_output($answer, &get_logfile(1));
 
 unlink('inc');