fix for path.join problem when both string start with a "..", a unit test has been added

src/host/path_join.c

@@ -71,6 +71,10 @@ int path_join(lua_State* L)
 				break;
 			}
 
+			if (start[0] == '.' && start[1] == '.' && start[2] == '\0'){
+				break;
+			}
+
 			/* otherwise trim segment and the ".." sequence */
 			if (start != buffer) {
 				--start;

tests/base/test_path.lua

@@ -267,6 +267,10 @@
 		test.isequal("", path.join("p1/p2/", "../.."))
 	end
 
+	function suite.join_OnBothUpTwoFolders()
+		test.isequal("../../../../foo", path.join("../../", "../../foo"))
+	end
+
 	function suite.join_OnUptwoFolders()
 		test.isequal("p1/foo", path.join("p1/p2/p3", "../../foo"))
 	end