The __dead definition in defines.h redefines it to be __attribute__(noreturn) -- which works fine if the OS's sys/cdefs.h uses the same definition, or if the symbol wasn't previously defined.

However, Interix uses (and provides) the older BSD definition for __dead, which is "volatile".  That can't live after the arguments; it would have to be placed before the return type.

A better solution here would be to use __attribute__(noreturn) explicitly and do away with playing __dead (pun intended).