Comment 5 for bug 321848

I had a quick look, and re-adding in the #ifdef in src/keymap.c was basically what I was going to propose too. The implementation looks the same as what it was in 0.17.4, so I think it's probably ok. However, it might be a good idea to get someone who knows vte a bit better to have a quick look at it (I might be wrong, but I think Kees Cook might be a good person to ask)