I have a Linux Mint system that was pretty far behind in updates. I'd been building kstars/Ekos on it for a few years up until maybe 6 months ago but not certain. Since then, I could not get kstars to compile. As my other (newer) systems worked fine I decided to upgrade to 18.3 (Xenial). Unfortunately this did not help, and I am getting the same error which is below. I forced a re-install of all dependencies and this did not help. I also re-downloaded the git repository and started fresh with no success.
Any ideas what is causing this and how to fix it?
[ 85%] Building CXX object kstars/CMakeFiles/KStarsLib.dir/fitsviewer/fitssepdetector.cpp.o
In file included from /home/schwim/src/kstars/kstars/fitsviewer/fitssepdetector.cpp:22:0:
/home/schwim/src/kstars/kstars/fitsviewer/sep/sep.h:233:31: error: variable or field ‘sep_set_extract_pixstack’ declared void
void sep_set_extract_pixstack(size_t val);
/home/schwim/src/kstars/kstars/fitsviewer/sep/sep.h:233:31: error: ‘size_t’ was not declared in this scope
/home/schwim/src/kstars/kstars/fitsviewer/sep/sep.h:234:1: error: ‘size_t’ does not name a type