Fix false DECLFILENAME on black-boxed modules (#2430).

src/V3LinkCells.cpp

@@ -201,6 +201,7 @@ private:
             UINFO(2, "Link Module: " << nodep << endl);
             if (nodep->fileline()->filebasenameNoExt() != nodep->prettyName()
                 && !v3Global.opt.isLibraryFile(nodep->fileline()->filename())
+                && !VN_IS(nodep, NotFoundModule)
                 && !nodep->recursiveClone() && !nodep->internal()) {
                 // We only complain once per file, otherwise library-like files
                 // have a huge mess of warnings