After experimenting with a modified cairo_test program that draws both with
cairo and with regular FLTK drawing functions to the same window, it seems
necessary to control for possible changes to the graphics context made by
cairo in Fl_Cocoa_Window_Driver::make_current() rather than in
cairo_create_surface().
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@13119 ea41ed52-d2ee-0310-a9c1-e6b18d33e121