Glenn Thobe and Chris Lewis have ported mgetty+sendfax to AT&T’s 3B1 machines, it should compile without changes to the source (but define -D_3B1_ in the Makefile).
These ports are to two different environments:
Glenn’s port was with GCC (ANSI C) and an add-on select() library routines. Chris’s port was with stock 3b1 C, without select(). Both seem reliable.
Some further hints concerning a select() library and the pbmplus tools can be found in the file contrib/3b1 which are the notes from Glenn’s port.
Chris’s port relies simply on the suggested definitions (especially
-DUSE_READ) in the Makefile. Chris suggests that you use select()
if you already have it for some other reason, but that it seems to work
just fine without it.
Right now, I think mgetty won’t compile with the standard C compiler (it will with gcc), because the stuff I do in the conf_*.c source files is a little bit too hard for it. I’ll work on it.