Assuming a wingsuit with a 2-1 glide ratio (2 meters forward, 1 meter down), we should be able to create a massive net to catch the halfling. Wingsuits typically start gliding at approx 30mph (which is approx 13 m/s, taking approx 1.365 seconds to reach).
Rough calculation (probably not that accurate):
Starting from 100 meters up, jumping forwards, taking 1.365 seconds to reach wingsuit glidable speed, the halfling has already dropped ~9.136 meters, leaving ~91 meters to drop. If we go with a straight up conversion using the glide ratio assumed, our maximum distance traveled is 182 meters forward - but this would leave us splat on the ground, so we need to reduce this.
Let us assume the following setup.
| badly drawn net |
| x __ | ^
| -- | 100m
| \- | v
| \-_ _ /|
X marks the target for the halfling, where he should aim to start contacting the net. The net will be roughly U shaped with the outer end much higher than the end point. The point of the catcher is to change his downards trajectory as gently as possible into a horizontal trajectory, until we can change it into an upwards trajectory where gravity will slow him down to safety. By using a curved net, we can acheive this - kind of like how skateboarders eventually settle down in the middle of a halfpipe.
However, all that is speculation without actual math, so lets do some math.
A 91 meter drop allows you to drop for 4.30799664301 seconds before hitting the ground. During that time you will have traveled 182 meters forward, but you would have hit the ground at a speed of 39.2266 meters per second, enough to kill your halfling. Assuming your net is large enough and your target tree is really far away, you could potentially allow for a full flight time of 2 + 1.365 seconds, where he would have dropped his altitude by a total of 55.5214522231 meters - we subtract the initial 9.1 meters, leaving him with leaving him with a total distance traveled of about 90 meters forwards (Enough to fly over a river or a small hill or something like that). At that point, he is plummeting at 32.99937725 meters per second, which is quite dangerous. This is where your halfling should reach the top of the net and begin to roll down it. He'll have 45 meters (roughly) of netting to roll through, while friction and the net slow him down, eventually to the point of safety.
In short: From a 100 meter drop, the halfling can fly 90 meters forwards before probably needing to hit the catcher.
Note: You may have noticed I didn't actually do the math for how long it would take the net to stop him, or how far he would have to roll. This is because I don't know how to do the math for that part. If anyone does, please feel free to edit this answer to include the proper maths.
Note 2: I used this site for the calculations.