This can actually be a consequence of `libxfont1` package no longer built with `--enable-fc`, i. e. X server (which depends on `libxfont2`) is no longer capable of understanding the `tcp/host:7100`, `inet/host:7100` and `unix/:7100` font path URL syntax.
So this bug is related to bug #927375, and, until it's fixed, both `libxfont1` and `libxfont2` packages should claim they're breaking `xfstt` in exactly the same manner they're currently breaking `xfs` (from Debian 7). -- Regards, Andrey ``Bass'' Shcheglov.