Pull up following revision(s) (requested by flxd in ticket #29):
external/gpl3/gcc/dist/gcc/config/vax/builtins.md: revision 1.6
Fix PR port-vax/51761 as suggested by Paul Koning on port-vax list.
Installation (install.ram, -Os) on my VS4000 is possible without SCSI
timeouts again.
Other variable-length bit field instructions should be checked for correct
constraints, too!

(snj)