Bug 1045139 - The Arabic text with "MS Sans Serif" font is rendered bad
https://bugzilla.mozilla.org/show_bug.cgi?id=1045139
This is only enabled on Windows platforms, and requires support from
Uniscribe to work. But for clients that do hook up to Uniscribe, this
fixes shaping of Windows-1256-encoded bitmap fonts like "MS Sans Serif".
The code and table together have just less than a 1kb footprint when
enabled.
UNTESTED. I might even have broken regular Arabic fallback shaping.