@Eric-Katzfey so I also tried deleting /usr/include/gphoto2, and it still gave the same error. I don't think I had installed gphoto2 separately, but it wasn't a completely clean install. I had to install ROS melodic, and it uninstalled parts of the voxl sdk, and I was trying to reinstall voxl-suite. I don't necessarily need gphoto2, but it's part of what apt tries to install when I run apt install voxl-suite.
Side question: I saw that there was /opt/ros/melodic that came with the voxl image, but there was no setup.bash to source, or is this located elsewhere on the system?