message: Fixes build error, again (FreeBSD related).
diff: @@ -9,10 +9,15 @@ option(CONTOUR_VT_METRICS "Enables collecting and exit-printing some VT usage me
  option(CONTOUR_SCROLLBAR "Enables scrollbar in GUI frontend." ON)
  option(CONTOUR_BUILD_WITH_QT6 "Use Qt 6" OFF)
  +set(QtX11Extras)
  +if(NOT(WIN32) AND NOT(APPLE))
  + set(QtX11Extras X11Extras)
  +endif()
  +
  if(CONTOUR_BUILD_WITH_QT6)
  - find_package(Qt6 COMPONENTS Core Gui Network OpenGL OpenGLWidgets Widgets Multimedia X11Extras REQUIRED)
  + find_package(Qt6 COMPONENTS Core Gui Network OpenGL OpenGLWidgets Widgets Multimedia ${QtX11Extras} REQUIRED)
  else()
  - find_package(Qt5 COMPONENTS Gui Network Widgets Multimedia X11Extras REQUIRED) # apt install qtbase5-dev libqt5gui5
  + find_package(Qt5 COMPONENTS Gui Network Widgets Multimedia ${QtX11Extras} REQUIRED) # apt install qtbase5-dev libqt5gui5
  endif()
  add_subdirectory(display)
  