col: respect POSIX

[bapt]

Summary

Makes col(1) respect posix again for escape sequences as decribed in its manpage
The bug was introduced in CSRG in 1991
This also reverts r280911

Test Plan

using heirloom doctools's tbl and nroff rendering share/doc/usd/10.exref/summary/ex.summary
tbl -Tlp ex.summary | nroff -Tlp -ms | /usr/bin/col -x | less

[eadler]

usr.bin/col/col.c

380–381

having these as named constants would be nice.

[jhb]

It was broken in 1990 instead of 1991. :)

usr.bin/col/col.c

380

I wonder if this shouldn't be using the constants here (ESC, FHLF, etc.). I think it might be clearer if it did?

[bapt]

usr.bin/col/col.c

380–381

None of the PUTC uses the name constant so one would have to go through the whole code to change it everywhere while this is a good idea it should be done in a separate commit

[bdrewery]

You say "reverts r280911" but it is removing casts. I don't see that in your diff.

[imp]

head/usr.bin/col/col.c

381 ↗

(On Diff #5142)

Any reason not to use FHLF instead of the bare '9' here?

[bapt]

I wanted to separate in 2 commits, now it uses the defines for all PUTC where accurate