added configure check for wcsdup(), there are too many Unix systems without it

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46956 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

setup.h_vms

@@ -997,6 +997,9 @@ typedef pid_t GPid;
 /* Define if you have wcslen function  */
 #define HAVE_WCSLEN 1
 
+/* Define if you have wcsdup function  */
+#define HAVE_WCSDUP 0
+
 /* Define if you have wcstoull() and wcstoll() */
 #undef HAVE_WCSTOULL