Add Carbon and Cocoa dependencies to vncviewer

We use both frameworks directly from vncviewer so we should
make sure they get pulled in.
diff --git a/vncviewer/CMakeLists.txt b/vncviewer/CMakeLists.txt
index c6e778f..de9da8f 100644
--- a/vncviewer/CMakeLists.txt
+++ b/vncviewer/CMakeLists.txt
@@ -48,6 +48,10 @@
 
 target_link_libraries(vncviewer rfb network rdr os Xregion ${FLTK_LIBRARIES} ${GETTEXT_LIBRARIES})
 
+if(APPLE)
+  target_link_libraries(vncviewer "-framework Cocoa" "-framework Carbon")
+endif()
+
 install(TARGETS vncviewer DESTINATION ${BIN_DIR})
 if(UNIX)
   install(FILES vncviewer.man DESTINATION ${MAN_DIR}/man1 RENAME vncviewer.1)