* config.guess (pc:*:*:*): Return i586-pc-msdosdjgpp, for

consistency with config.sub.  (Update from upstream sources.)

config.guess

@@ -1115,8 +1115,11 @@ EOF
     pc:*:*:*)
 	# Left here for compatibility:
         # uname -m prints for DJGPP always 'pc', but it prints nothing about
-        # the processor, so we play safe by assuming i386.
-	echo i386-pc-msdosdjgpp
+        # the processor, so we play safe by assuming i586.
+	# Note: whatever this is, it MUST be the same as what config.sub
+	# prints for the "djgpp" host, or else GDB configury will decide that
+	# this is a cross-build.
+	echo i586-pc-msdosdjgpp
         exit ;;
     Intel:Mach:3*:*)
 	echo i386-pc-mach3