config.sub: correct Bull DPX/2-[123]00 and DPX/20 canonical names.

config.sub was mapping all single-component shorthands matching the
shell glob `dpx2*` to ‘m68k-bull-sysv3’, which is incorrect.  Of the
four different machines once manufactured by Groupe Bull whose model
number can be abbreviated ‘dpx2something’, only two were m68k-based:
the DPX/2-200 and DPX/2-300.  The DPX/2-100, on the other hand, had an
i386 CPU.  And the DPX/20 was a completely different beast, released
years later and based on the POWER architecture.

I’ve chosen to keep making ‘dpx2’ map to ‘m68k-bull-sysv3’ as the
DPX/2-200 and /2-300 seem to have been the most widely used.  config.sub
now understands ‘dpx2100’, ‘dpx2200’, and ‘dpx2300’ as shorthands for
‘i386-bull-sysv3’, ‘m68k-bull-sysv3’, and ‘m68k-bull-sysv3’ respectively.
It also accepts ‘dpx21xx’, ‘dpx22xx’, and ‘dpx22xx’ as equivalent to
these, but no other variations; in particular, ‘dpx2xxx’, which was in
the test suite, no longer works, as it is ambiguous.

(As far as I can tell, there weren’t actually any submodels of any of
these systems, so I could be persuaded to remove the …xx aliases.
I kept them mainly because of the test suite formerly testing dpx2xxx.)

Finally ‘dpx20’ now maps to ‘rs6000-bull-bosx’.  Both the ‘rs6000’ and
‘bosx’ components of this name are debatable, but I *think* it is what
config.guess would do on this machine.

Sources for Bull DPX/2whatever history:

 - https://oldskool.silicium.org/stations/bull_dpx20.htm
 - https://www.feb-patrimoine.com/english/bull_dpx2.htm
 - https://www.feb-patrimoine.com/english/unix_and_bull.htm

Note in particular “Que cette machine soit estampillée BULL ou IBM,
elle faisait tourner AIX (l'Unix d'IBM)” on the first of these pages,
which is why I say “bosx” is debatable…

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>

config.sub

@@ -4,7 +4,7 @@
 
 # shellcheck disable=SC2006,SC2268,SC2162 # see below for rationale
 
-timestamp='2024-03-12'
+timestamp='2024-05-27'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -195,6 +195,7 @@ case $1 in
 					| apple \
 					| att* \
 					| axis \
+					| bull \
 					| c[123]* \
 					| cbm \
 					| cisco \
@@ -771,10 +772,22 @@ case $basic_machine in
 		cpu=m68k
 		vendor=motorola
 		;;
-	dpx2*)
+	# This used to be dpx2*, but that gets the RS6000-based
+	# DPX/20 and the x86-based DPX/2-100 wrong.  See
+	# https://oldskool.silicium.org/stations/bull_dpx20.htm
+	# https://www.feb-patrimoine.com/english/bull_dpx2.htm
+	# https://www.feb-patrimoine.com/english/unix_and_bull.htm
+	dpx2 | dpx2[23]00 | dpx2[23]xx)
 		cpu=m68k
 		vendor=bull
-		basic_os=sysv3
+		;;
+	dpx2100 | dpx21xx)
+		cpu=i386
+		vendor=bull
+		;;
+	dpx20)
+		cpu=rs6000
+		vendor=bull
 		;;
 	encore | umax | mmax)
 		cpu=ns32k
@@ -1077,9 +1090,13 @@ case $cpu-$vendor in
 		vendor=alt
 		basic_os=${basic_os:-linux-gnueabihf}
 		;;
-	dpx20-unknown | dpx20-bull)
-		cpu=rs6000
-		vendor=bull
+
+	# Normalized CPU+vendor pairs that imply an OS,
+	# if not otherwise specified
+	i386-bull | m68k-bull)
+		basic_os=${basic_os:-sysv3}
+		;;
+	rs6000-bull)
 		basic_os=${basic_os:-bosx}
 		;;