use traits.d(externDmangle)

Author: rainers

src/core/internal/traits.d

@@ -88,19 +88,9 @@ private template substInoutForm(T)
 /// used to declare an extern(D) function that is defined in a different module
 template externDFunc(string fqn, T:FT*, FT) if(is(FT == function))
 {
-    static if (is(FT RT == return) && is(FT Args == function))
-    {
-        import core.demangle : mangleFunc;
-        enum decl = {
-            string s = "extern(D) RT externDFunc(Args)";
-            foreach (attr; __traits(getFunctionAttributes, FT))
-                s ~= " " ~ attr;
-            return s ~ ";";
-        }();
-        pragma(mangle, mangleFunc!T(fqn)) mixin(decl);
-    }
-    else
-        static assert(0);
+    alias _wrap(alias T) = T; // fool the parser
+
+    alias externDFunc = _wrap!(__traits(externDmangle, fqn, FT));
 }
 
 template staticIota(int beg, int end)