This PKGBUILD builds urxvt-unicode with the patch from https://github.com/blueyed/rxvt-unicode/tree/display-wide-glyphs to display glyhps that are too wide instead of a square.

urxvt considers the font to be broken, e.g. if the glyph is wider than the number of cells that wcwidth(3) reports. This gets better with Unicode 9 (since e.g. more characters are assigned a width of 2), but it does not help with characters from the Private Use Area (e.g. Font Awesome).

I am coming back to this approach after blueyed/rxvt-unicode#1 turned out to be too fragile:

1. the method of using a socket for communication fails for remote applications, and already when re-attaching to a tmux session after closing the terminal it was started from (where the terminal cannot respond to requests on the socket then anymore).
2. using OSC terminal escape sequences also does not work with tmux (server), and other applications that have no tty attached.

Included in Arch's user repository (AUR): https://aur.archlinux.org/packages/rxvt-unicode-cvs-patched-wideglyphs/