gcc.texi redefining \defbf

[karl at freefriends dot org (Karl Berry)]

I happened to notice today that gcc.texi redefines the \defbf font:

  @c Change the font used for @def... commands, since the default
  @c proportional one used is bad for names starting __.
  @tex
  \global\setfont\defbf\ttbshape{10}{\magstep1}
  @end tex

It doesn't say what "bad" means, and I don't ever remember seeing a bug
report about it, but I'm guessing it's that the two _'s run together,
similarly the second _ runs into the next character.  (Well, they don't
literally run into each other, but they are awfully close.)

So I experimented with changing the definition of \_ to add some space
after the _, and came up with:
\def\_{\leavevmode \kern.07em \vbox{\hrule width.3em height.1ex}\kern .07em }

The old definition was:
\def\_{\leavevmode \kern.07em \vbox{\hrule width.3em height.1ex}}

I didn't put this into the released texinfo.tex yet, in case you wished
to try it and see if it suits.

Thanks,
karl (texinfo maintainer)