On sun4m machine, mkraid aborts with a kernel message "Unimplemented SPARC system call 140". I tried compiling raidtools-19990713-0.90.tar.gz and received the same error. If I #define __usparc__ in raid_io.c, mkraid seems to work ok but then very strange things happen on the system identical to Bug ID 2807 (e.g. running vi gives cannot execute binary file /bin/vi).
Fixed in the new raidtools avalable from rawhide.