fix return address to local variable

alib2std/src/extensions/foreach.hpp

@@ -66,14 +66,14 @@ public:
 		return *this;
 	}
-	const_pair_foreach_iterator& operator++(int) {
+	const_pair_foreach_iterator operator++(int) {
 		const_pair_foreach_iterator temp = *this;
 		++current1;
 		++current2;
 		return temp;
 	}
-	const_pair_foreach_iterator& operator--(int) {
+	const_pair_foreach_iterator operator--(int) {
 		const_pair_foreach_iterator temp = *this;
 		--current1;
 		--current2;

alib2std/src/extensions/set.hpp

@@ -101,13 +101,13 @@ public:
 		return *this;
 	}
-	set_move_iterator& operator++(int) {
+	set_move_iterator operator++(int) {
 		set_move_iterator temp = *this;
 		++current;
 		return temp;
 	}
-	set_move_iterator& operator--(int) {
+	set_move_iterator operator--(int) {
 		set_move_iterator temp = *this;
 		--current;
 		return temp;

alib2std/src/extensions/vector.hpp

@@ -56,13 +56,13 @@ public:
 		return *this;
 	}
-	ptr_vector_iterator& operator++(int) {
+	ptr_vector_iterator operator++(int) {
 		ptr_vector_iterator temp = *this;
 		++current;
 		return temp;
 	}
-	ptr_vector_iterator& operator--(int) {
+	ptr_vector_iterator operator--(int) {
 		ptr_vector_iterator temp = *this;
 		--current;
 		return temp;