Please reinstate the 'nv-drm-343.36.patch' patch. X fails to start without this patch. I applied the patch to nvidia-346.35-2 package and X starts again.
Xorg log file shows the following without the patch then refuses to start (nvidia kernel module is loaded):

[ 42.058] (EE) systemd-logind: failed to get session: PID 349 does not belong to any known session
[ 42.058] (II) xfree86: Adding drm device (/dev/dri/card0)
[ 42.058] (EE) /dev/dri/card0: failed to set DRM interface version 1.4: Invalid argument
[ 42.059] (--) PCI:*(0:1:0:0) 10de:0de1:3842:1430 rev 161, Mem @ 0xfd000000/16777216, 0xe8000000/134217728, 0xf0000000/33554432, I/O @ 0x0000b000/128, BIOS @ 0x????????/524288
[ 42.059] (WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
[ 42.064] (II) LoadModule: "glx"
[ 42.183] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[ 44.553] (II) Module glx: vendor="NVIDIA Corporation"
[ 44.553] compiled for 4.0.2, module version = 1.0.0
[ 44.553] Module class: X.Org Server Extension
[ 44.560] (II) NVIDIA GLX Module 346.35 Sat Jan 10 20:53:39 PST 2015
[ 44.571] (==) Matched nouveau as autoconfigured driver 0
[ 44.571] (==) Matched nv as autoconfigured driver 1
[ 44.571] (==) Matched modesetting as autoconfigured driver 2
[ 44.571] (==) Matched fbdev as autoconfigured driver 3
[ 44.571] (==) Matched vesa as autoconfigured driver 4
[ 44.571] (==) Assigned the driver to the xf86ConfigLayout
[ 44.571] (II) LoadModule: "nouveau"
[ 44.598] (WW) Warning, couldn't open module nouveau
[ 44.598] (II) UnloadModule: "nouveau"
[ 44.598] (II) Unloading nouveau
[ 44.598] (EE) Failed to load module "nouveau" (module does not exist, 0)
[ 44.598] (II) LoadModule: "nv"
[ 44.598] (WW) Warning, couldn't open module nv
[ 44.598] (II) UnloadModule: "nv"
[ 44.598] (II) Unloading nv
[ 44.598] (EE) Failed to load module "nv" (module does not exist, 0)
[ 44.598] (II) LoadModule: "modesetting"
[ 44.598] (WW) Warning, couldn't open module modesetting
[ 44.598] (II) UnloadModule: "modesetting"
[ 44.598] (II) Unloading modesetting
[ 44.598] (EE) Failed to load module "modesetting" (module does not exist, 0)
[ 44.598] (II) LoadModule: "fbdev"
[ 44.599] (WW) Warning, couldn't open module fbdev
[ 44.599] (II) UnloadModule: "fbdev"
[ 44.599] (II) Unloading fbdev
[ 44.599] (EE) Failed to load module "fbdev" (module does not exist, 0)
[ 44.599] (II) LoadModule: "vesa"
[ 44.599] (WW) Warning, couldn't open module vesa
[ 44.599] (II) UnloadModule: "vesa"
[ 44.599] (II) Unloading vesa
[ 44.599] (EE) Failed to load module "vesa" (module does not exist, 0)
[ 44.599] (EE) No drivers available.
[ 44.648] (EE)
Fatal server error:
[ 44.648] (EE) no screens found(EE)
[ 44.648] (EE)
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.
[ 44.648] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[ 44.648] (EE)