Remove very old and unused signal information codes.

[jhb]

Summary

These have been supplanted by the MI signal information codes in
<sys/signal.h> since 7.0. The FPE_*_TRAP ones were deprecated even
earlier in 1999.

Test Plan

• waiting on a tinderbox to finish, but I'm quite certain these aren't used anywhere

[kib]

sys/x86/include/signal.h

48

I do not object against this part, but the pollution might be relied upon by third-party software. I do not know.

sys/x86/include/trap.h

88

At least BUS_PAGE_FAULT is used in kernel.

[jhb]

sys/x86/include/signal.h

48

I can request an exp-run to check for this.

sys/x86/include/trap.h

88

This is only for legacy binaries though (< 7.0), so I think we can just hide that specific use case under #ifdef _KERNEL. We could also make the tunable depend on #ifdef COMPAT_FREEBSD6? (And just always use SIGSEGV on kernels without COMPAT_FREEBSD6?) Alternatively, the compat shim could just use 'T_PAGEFLT' directly for ucode (this matches what the code did prior to the siginfo commit).

[kib]

sys/x86/include/signal.h

48

Ok.

sys/x86/include/trap.h

88

I do not see a reason to not use T_PAGEFLT directly.

[jhb]

• Use T_PAGEFLT directly for the legacy page fault signal code.
• Use T_PAGEFLT on i386 as well.
• Add <machine/trap.h> #include's.