After I made this module, I read the sim800l manual. The sim800l under some circumstances can draw 2A and thus this power supply is not big enough. There are 2A boost modules readily available some even have Fritzing parts (the lm2596 for instance, which is recommended in the data sheet, is on core parts.) In any case here is the requested booster as it is made now.
0.9v-5V-booster-usb-output.fzpz (6.3 KB)
on to the GSM module.
edit:
Problem number2, the GSM module wants 4V not 5V
Specification
Supply voltage: 3.8V - 4.2V
Recommended supply voltage: 4V
The LM2596 is a step down regulator and thus would need 5V to produce a 4V output. You could (as they suggest) use a LIPO battery (3.7 to 4.2V) directly. Otherwise depending on your input voltage you may need to find a 2A adjustable output boost/buck module (which can take an input voltage both lower or higher than the output voltage) to power this. There are lots of such modules available and may be some with Fritzing parts. If not they are easy to create.
edit2:
OK here is the Sim module. Note the pin placement is from a jpg file and may well not be correct. Before ordering boards print out the footprint at 1:1 scale and compare it to a real board to make sure the pins are in the correct place.
edit (feb 2022)
replaced the part with one with the correct pin width (the pins are not on a 0.1in boundary!)
sim800L-red-breakout-module-21-5mm-width.fzpz (7.6 KB)
Peter