Change test for [which make] to [which sh]

ChangeLog

@@ -11,6 +11,11 @@
 	* testsuite/lib/runtest.exp (runtest_copy_nested_testsuite_log):
 	New procedure.  Dumps log from nested run into main test log.
 
+	* testsuite/runtest.libs/utils.test: Change test for [which make]
+	to [which sh] because make(1) is not always available on non-GNU
+	systems but sh(1) exists on any Unix.  GNU make is often installed
+	as "gmake" on non-GNU systems and may be the only "make" utility.
+
 	* testsuite/runtest.main/pr42399.exp (test_pr42399): Revise to
 	ensure that a failure to produce any output at all in the inner
 	test will be detected.  This was discovered on Solaris 10.

testsuite/runtest.libs/utils.test

@@ -139,12 +139,12 @@ if {[which [file join $objdir .. config.status]] != 0} {
   fail "which, absolute path to config.status"
 }
 
-# Test 'which make'.
+# Test 'which sh'.
 #
-if {[which make] != 0} {
-  pass "which, make"
+if {[which sh] != 0} {
+  pass "which, sh"
 } else {
-  fail "which, make"
+  fail "which, sh"
 }
 
 ### Do not adjust the comment on the next line. The grep test case