-VMS and MS-DOS builds are probably broken right now. If you are able
-to build Bison on either platform and you need to make changes to do
-so, please submit those changes as a bug report. On VMS, you will
-probably have to create Makefile from Makefile.in by hand. Remember
-to do `SET COMMAND BISON' to install the data in `BISON.CLD'.
+Bison can work with pre-1.4.6 distributions of GNU m4 if they are
+sufficiently patched, but if you encounter a bug with an older
+distribution and report a bug we will probably suggest that you
+upgrade to 1.4.6 as the first step in trying to fix it.