I want to know what internal macros are defined,
so I did cpp -dM (this works on unices, with a ctrl-D):
cc1.exe: stdout: Invalid argument
cc1.exe: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://www.mingw.org/bugs.shtml> for instructions.
"cpp -dM <randomfile>" works as intended, so this is not
a serious problem, just unexpected. with Mingw 5.0.2