diff --git a/lib/diagnostics.h b/lib/diagnostics.h
index 6ab71d1fbe..790fb35209 100644
--- a/lib/diagnostics.h
+++ b/lib/diagnostics.h
@@ -252,7 +252,7 @@ extern format_backtrace_line_t format_backtrace_line;
 
 #if defined(__MINGW32__) || defined(__CYGWIN32__)
 #define BOINCASSERT(expr)   assert(expr)
-#define BOINCTRACE(...)     boinc_trace
+#define BOINCTRACE          boinc_trace
 #else  // __MINGW32__
 #define BOINCASSERT(expr)   __noop
 #define BOINCTRACE          boinc_trace
@@ -274,7 +274,7 @@ extern format_backtrace_line_t format_backtrace_line;
 
 #define BOINCASSERT(expr)         
 #ifndef IRIX
-#define BOINCTRACE(...)          
+#define BOINCTRACE          
 #endif
 
 #endif // _DEBUG