NetBSD 1.5 is lacking ecvt, fcvt, gcvt for crtdll.

diff --git a/include/config.h.in b/include/config.h.in
index 5e9ec88..932810c 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -178,6 +178,9 @@
 /* Define if you have the dlopen function.  */
 #undef HAVE_DLOPEN
 
+/* Define if you have the ecvt function.  */
+#undef HAVE_ECVT
+
 /* Define if you have the finite function.  */
 #undef HAVE_FINITE