cgen: always use tmp vars in return_statement()

vlib/v/gen/c/cgen.v

@@ -4745,7 +4745,8 @@ fn (mut g Gen) return_statement(node ast.Return) {
 			g.writeln('return $opt_tmp;')
 			return
 		}
-		free := g.is_autofree && !g.is_builtin_mod // node.exprs[0] is ast.CallExpr
+		// free := g.is_autofree && !g.is_builtin_mod // node.exprs[0] is ast.CallExpr
+		free := !g.is_builtin_mod // node.exprs[0] is ast.CallExpr
 		mut tmp := ''
 		if free {
 			// `return foo(a, b, c)`
@@ -4777,7 +4778,9 @@ fn (mut g Gen) return_statement(node ast.Return) {
 			// autofree before `return`
 			// set free_parent_scopes to true, since all variables defined in parent
 			// scopes need to be freed before the return
+			if g.pref.autofree {
 				g.autofree_scope_vars(node.pos.pos - 1, node.pos.line_nr, true)
+			}
 			if tmp != '' {
 				g.write('return $tmp')
 			}

vlib/v/gen/c/fn.v

@@ -421,7 +421,8 @@ fn (mut g Gen) call_expr(node ast.CallExpr) {
 	} else {
 		''
 	}
-	if gen_or && g.pref.autofree && g.inside_return {
+	// if gen_or && g.pref.autofree && g.inside_return {
+	if gen_or && g.inside_return {
 		// TODO optional return af hack (tmp_count gets increased in .return_statement())
 		g.tmp_count--
 	}

vlib/v/tests/option_test.v

@@ -364,7 +364,6 @@ struct MultiOptionalFieldTest {
 	b ?int
 }
 
-/*
 fn foo() ?int {
 	return 0
 }
@@ -380,4 +379,3 @@ fn test_return_or() {
 	x := foo2() or { return }
 	assert x == 0
 }
-*/