[Groff] Bug in .ev and \m

[Bob Diertens]

Hi,

When switching back to the previous font in another environment
something goes wrong.
Consider the input:

\m[blue]
blue
.br
.ev new
blue
\m[red]
red
\m[]
blue
.br
.ev
blue
\m[red]
red
\m[]
blue

The third and fourth blue are in black. It seems like the previous
glyph color is not recorded properly in the environment new.
Can't find this in the code.

Gr,
    Bob