Included FLTK depends on libdl


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4672 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b9b327f..1d8645a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -315,6 +315,9 @@
     if(APPLE)
       set(FLTK_LIBRARIES "-framework Carbon -framework Cocoa -framework ApplicationServices")
     endif()
+    if(NOT WIN32)
+      set(FLTK_LIBRARIES "-ldl")
+    endif()
     message(STATUS "Using included FLTK library")
   endif()