Apart from being the capital of Egypt, Google tells me it's also a graphics library targeted for (among others) the X Window System (X11).
First, isn't Linux using GTK, and isn't GTK mutually exclusive with X11?
Why is CMake searching for cairo.h if my wxWidgets build is configured for Ubuntu?

More to the point, how exactly is Cairo used within wxWidgets in relation to native build systems? Given that a wxWidgets-build for Ubuntu also needs the cairo header file, is it trying to interface to a package that is supposed to be installed on the OS or is it needed in some other way? Why is there a cairo.cpp present in the wxWidgets folder but not a cairo.h?
sorry for the TL;DR, but any clarity in this question would be greatly appreciated
