How to build CGAL with tracing enabled (esp CGAL_NEF_TRACEN)

I am trying to debug an asse开发者_StackOverflow中文版rtion failure exception I get with the CGAL library. CGAL has well placed debug and trace statements all over the library, which I can use to understand what's happening in my case. However despite many efforts I could not find the right compile time flags that will enables those debug and trace messages. I am especially interested in the trace messages printed with the CGAL_NEF_TRACEN macro. I have tried to compile with the cmake option -DCMAKE_BUILD_TYPE=Debug, but to no avail. I don't have much experience with cmake. Please let me know if you know how to do this.

Got the answer on cgal-discuss mailing list. Compile a debug version and set the global variable debugthread to 0.