The code used in configure.ac to check for struct __res_state _res is an extern, can fail. I'm porting the code to UWIN, (Unix on Windows, available at http://www2.research.att.com/~gsf/download) using Microsoft Visual Studio for the cc compiler. The code in lines 3483 - 3491 should include a reference to _res, to verify the compiler doesn't ignore non-referenced variables. I suggest line 3491 should be changed from: Int main() { return 0; } To Int main() { _res.retrans=0; return 0; } Thank you for your consideration. Jeff Fellin