[screen-devel] Display log filename in the hardstatus

[Kieran Bingham]

So this is the patch that caused me to scratch the itch, and then
got distracted looking at build and compiler warnings.

The aim is to provide an escape code to allow the user to display
the active logging filename in the window.

I find this incredibly useful and have been utilising this for several
years. (I use screen as a terminal, and even a logged serial console)

I hope that you'll consider reviewing and integrating this; I posted
this a couple of years ago - but had no response.

Patch also available on github if you prefer to pull from there
rather than using git-am:
  https://github.com/kbingham/screen/tree/logfile

--
Regards

Kieran