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