If __extern is used in a header, extern.h is needed to resolve that to extern. Regards, Erik diff -urN klibc-0.202-pristine/include/sys/select.h klibc-0.202/include/sys/select.h --- klibc-0.202-pristine/include/sys/select.h 2002-08-09 08:27:31.000000000 +0200 +++ klibc-0.202/include/sys/select.h 2005-03-02 20:05:54.000000000 +0100 @@ -5,6 +5,7 @@ #ifndef _SYS_SELECT_H #define _SYS_SELECT_H +#include <klibc/extern.h> #include <sys/time.h> #include <sys/types.h>