fix missing typedef

Author: Enchufa2

inst/include/Rcpp/sugar/functions/sapply.h

@@ -22,9 +22,6 @@
 #ifndef Rcpp__sugar__sapply_h
 #define Rcpp__sugar__sapply_h
 
-// This used to be conditional on a define and test in compiler.h
-#include <type_traits> // ::std::result_of
-
 namespace Rcpp{
 namespace sugar{
 

inst/include/Rcpp/traits/result_of.h

@@ -40,12 +40,7 @@ struct result_of{
 
 template <typename T>
 struct result_of<T>{
-    typename T::result_type type ;
-} ;
-
-template <typename RESULT_TYPE, typename... Args>
-struct result_of< RESULT_TYPE (*)(Args...) >{
-    typedef RESULT_TYPE type ;
+    typedef typename T::result_type type ;
 } ;
 
 }