We can discover our x,y coordinate in the core mesh with an
mfspr instruction, multiply y by the core mesh width, and have
the core number without needing to ask the kernel.
The previous dummy definition (as type int) was fine in general, since
tile doesn't have floating-point registers, but it confused gdb's
configure, leading to later compile errors. This change also makes
prfpregset_t parallel to prgregset_t, which seems like generally the
right thing regardless of the non-existence of the actual registers :-)
(__ptrace_eventcodes): Add new value PTRACE_EVENT_SECCOMP from Linux 3.5.
(__ptrace_setoptions): Add new value PTRACE_O_TRACESECCOMP, adjust PTRACE_O_MASK.
