This change introduces a new test to config-sub.sh which runs every

config.guess expected triplet through config.sub so that we can check
that it is properly recognised. Sometimes, new triplets have been
added to config.guess without updating config.sub accordingly (eg,
Harris NightHawk machines running PowerUnix from the mid-1990s!)

	* config.sub (case $os): Match nsk* and powerunix. Don't later
	match nsk* and set os=nsk which removes the OS version number.
	* testsuite/config-guess.data: Tweak Unleashed test case.
	* testsuite/config-sub.sh (run_config_sub_with_guess_triplets):
	New test.

config.sub

@@ -1365,7 +1365,8 @@ case $os in
 	     | powermax* | dnix* | nx6 | nx7 | sei* | dragonfly* \
 	     | skyos* | haiku* | rdos* | toppers* | drops* | es* \
 	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
-	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi*)
+	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
+	     | nsk* | powerunix)
 	# Remember, each alternative MUST END IN *, to match a version number.
 		;;
 	qnx*)
@@ -1449,9 +1450,6 @@ case $os in
 	ns2)
 		os=nextstep2
 		;;
-	nsk*)
-		os=nsk
-		;;
 	# Preserve the version number of sinix5.
 	sinix5.*)
 		os=`echo $os | sed -e 's|sinix|sysv|'`