__declspec not _declspec
Include "err.h" not <err.h>
Include "roken.h" before "err.h"
Indent "#if" as "# if" within roken.h.in when CPP rules must be copied
into the generated "roken.h".
Correct verr() attribute to be ROKEN_LIB_NORETURN_FUNCTION.
Change-Id: I4289ecaba4a097175b4a5a1cde529b59038c72e3