Create a proper interface base class for the viewport's framebuffer
This allows us to gracefully fall back to the FLTK code in case the
platform specific code cannot be used.
diff --git a/vncviewer/CMakeLists.txt b/vncviewer/CMakeLists.txt
index c1facc6..9b815a3 100644
--- a/vncviewer/CMakeLists.txt
+++ b/vncviewer/CMakeLists.txt
@@ -7,9 +7,11 @@
menukey.cxx
CConn.cxx
DesktopWindow.cxx
+ FLTKPixelBuffer.cxx
UserDialog.cxx
ServerDialog.cxx
OptionsDialog.cxx
+ PlatformPixelBuffer.cxx
Viewport.cxx
parameters.cxx
keysym2ucs.c