0:2(9): preprocessor error: Redefinition of macro x

0:5(9): preprocessor error: Redefinition of macro abc

0:8(9): preprocessor error: Redefinition of macro foo

0:11(9): preprocessor error: Redefinition of macro bar

0:14(9): preprocessor error: Redefinition of macro biff

0:17(9): preprocessor error: Redefinition of macro oper