$NetBSD$

--- blitz/funcs.h.orig	2006-02-02 14:05:27.000000000 +0000
+++ blitz/funcs.h
@@ -583,6 +583,8 @@ struct Fn_isnan {
         // Some platforms define isnan as a macro, which causes the
         // BZ_IEEEMATHFN_SCOPE macro to break.
         return isnan(a); 
+#elif defined(_GLIBCXX_USE_C99_MATH) && !defined(_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC)
+        return BZ_MATHFN_SCOPE(isnan)(a);
 #else
         return BZ_IEEEMATHFN_SCOPE(isnan)(a);
 #endif
