make defined() error message tell about "var" type

Change-Id: I21d994ebaee2db0d9b114812a8f89bb680ca311e
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>
(cherry picked from qtbase/109e3fa0ae77dd911ff2bf9feb3ef5db4779299a)

src/shared/proparser/qmakebuiltins.cpp

@@ -1118,7 +1118,7 @@ QMakeEvaluator::VisitReturn QMakeEvaluator::evaluateBuiltinConditional(
     switch (func_t) {
     case T_DEFINED: {
         if (args.count() < 1 || args.count() > 2) {
-            evalError(fL1S("defined(function, [\"test\"|\"replace\"])"
+            evalError(fL1S("defined(function, [\"test\"|\"replace\"|\"var\"])"
                            " requires one or two arguments."));
             return ReturnFalse;
         }