Just for reference, using xserver from Jessie works (on an otherwise Sid install):
ii xserver-xorg 1:7.7+7 powerpc X.Org X server
ii xserver-xorg-core 2:1.16.4-1 powerpc Xorg X server - core server
ii xserver-xorg-input-all 1:7.7+14 powerpc X.Org X server -- input driver metapackage
ii xserver-xorg-input-evdev 1:2.9.0-2 powerpc X.Org X server -- evdev input driver
ii xserver-xorg-input-synaptics 1.8.1-1 powerpc Synaptics TouchPad driver for X.Org server
ii xserver-xorg-input-wacom 0.26.0+20140918-1 powerpc X.Org X server -- Wacom input driver
ii xserver-xorg-video-all 1:7.7+7 powerpc X.Org X server -- output driver metapackage
ii xserver-xorg-video-ati 1:7.5.0-1 powerpc X.Org X server -- AMD/ATI display driver wrapper
ii xserver-xorg-video-fbdev 1:0.4.4-1+b2 powerpc X.Org X server -- fbdev display driver
ii xserver-xorg-video-mach64 6.9.4-2 powerpc X.Org X server -- ATI Mach64 display driver
ii xserver-xorg-video-mga 1:1.6.3-2+b1 powerpc X.Org X server -- MGA display driver
ii xserver-xorg-video-modesetting 0.9.0-2 powerpc X.Org X server -- Generic modesetting driver
ii xserver-xorg-video-nouveau 1:1.0.11-1 powerpc X.Org X server -- Nouveau display driver
ii xserver-xorg-video-r128 6.9.2-1+b2 powerpc X.Org X server -- ATI r128 display driver
ii xserver-xorg-video-radeon 1:7.5.0-1 powerpc X.Org X server -- AMD/ATI Radeon display driver
ii xserver-xorg-video-savage 1:2.3.7-2+b2 powerpc X.Org X server -- Savage display driver
ii xserver-xorg-video-sisusb 1:0.9.6-2+b2 powerpc X.Org X server -- SiS USB display driver
ii xserver-xorg-video-tdfx 1:1.4.5-1+b2 powerpc X.Org X server -- tdfx display driver
ii xserver-xorg-video-trident 1:1.3.6-2+b2 powerpc X.Org X server -- Trident display driver
ii xserver-xorg-video-vesa 1:2.3.3-1+b3 powerpc X.Org X server -- VESA display driver