https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65902
--- Comment #5 from Bernd Edlinger <bernd.edlinger at hotmail dot de> --- Well, I thought maybe it would not hurt to be more permissive... At least math.h and stdlib.h include <cyg/infra/cyg_type.h> which contains something like this: #ifndef __cplusplus typedef cyg_halbool bool; # ifndef false # define false 0 # endif # ifndef true # define true (!false) # endif #endif