The newish canon eos m100 camera doesn't have a profile. It's an ef-m mount with a...well, i was going to say 1.6 crop but i notice that the other similar canon eos m cameras have had their profiles changed to 1.613 so i'm going to guess the m100 is the same.
Here's the profile addition i've made so that darktable correctly picks up the camera/lens combination i'm using:
<camera>
<maker>Canon</maker>
<model>Canon EOS M100</model>
<model lang="en">EOS M100</model>
<mount>Canon EF-M</mount>
<cropfactor>1.613</cropfactor>
</camera>
It is now available in the 0.3.95(alpha) database.