As of 2013, manual cars (at least Mazdas) can still be roll-started, as long as the engine computer has enough power to function.

My CX-5 even has a wireless-pushbutton start, not a physical-key-in-the-ignition start, but I've still been able to roll-start it when the battery is too dead to crank the starter motor but still has enough juice for the electronics (lowest I've seen is ~8v if I recall correctly, but don't quote me on that).

The process is pretty much the same: put the car's ignition into the "ON" position (in my case, press the pushbutton twice without touching the pedals -- once to ACC mode, then once to move from ACC to ON), then it's the same as normal: clutch-in, shift to your preferred gear, get rolling, and pop the clutch. Engine computer sees "oh, looks like the engine's spinning, let's add gas and spark" and you're good to go.

Anecdotally, I've seen the described behavior of the engine computer ("detects spinning and adds gas/spark, even if the initial motion wasn't from the starter motor") on automatic transmission vehicles, too. On a 2008 Chevrolet, I found that if you revved the engine up a bit (for inertia), turned the key to OFF, then quickly turned the key back to ON (without turning all the way to START), the engine computer will catch it and keep it running.