Populate the non-LOAD openbsd.syscalls section (and PT_OPENBSD_SYSCALL)
with {uint offset, uint syscall#} entries in libc & ld.so.
In libc a few syscall# entries (break, sigprocmask, _tfork, _threxit)
are duplicated because additional or inline uses occur (that situation
is handled elsewhere)
ok kettenis

Only require 4 byte alignment on ILP32 archs

Add XOR cookies for rp and sp. Switch from calling obsolete
sig{block,setmask} to directly using the sigprocmask syscall.
Remove longjmperror()-if-passed-real-sigcontext checks and the
filling in of sigcontext fields that longjmp ignores.

in snaps; ok deraadt@

Do provide hidden _libc_* aliases for sig{block,setmask} and use them in
the ASM *setjmp implementations.
Skip the PLT when calling them on amd64 (other archs to do this after testing)

ok miod@

Remove wrong check.

HPPA longjmp tests that the env parameter < the current stack pointer.
The test relies on the stack being at the end of the memory space.

This test is wrong for a couple of reasons:
- the main stack is at 0x78000000-0x80000000, but allocations between
0x80000000-0xc0000000 are available to the program,
- pthread stacks may be at any place in the address space, allowing a
heap-allocated env parameter to fail the check.

ok deraadt@, kettenis@, guenther@ at least

zap rcsid.
okay deraadt@ (tested them all)

Remove the advertising clause in the UCB license which Berkeley
rescinded 22 July 1999. Proofed by myself and Theo.

reversed condition checking for sig*jmp(, savemask)

deal w/ longjmp(, 0)

fix typo, and put back stack frame ops

reverse condition in the sp botchness check, we need to nullify
if we are ok not if we are bad. fix a pasto in branch w/in longjmps.

implement the setjmp/longjmp family, based on fredette@'s work

Only require 4 byte alignment on ILP32 archs

Add XOR cookies for rp and sp. Switch from calling obsolete
sig{block,setmask} to directly using the sigprocmask syscall.
Remove longjmperror()-if-passed-real-sigcontext checks and the
filling in of sigcontext fields that longjmp ignores.

in snaps; ok deraadt@

Do provide hidden _libc_* aliases for sig{block,setmask} and use them in
the ASM *setjmp implementations.
Skip the PLT when calling them on amd64 (other archs to do this after testing)

ok miod@

Remove wrong check.

HPPA longjmp tests that the env parameter < the current stack pointer.
The test relies on the stack being at the end of the memory space.

This test is wrong for a couple of reasons:
- the main stack is at 0x78000000-0x80000000, but allocations between
0x80000000-0xc0000000 are available to the program,
- pthread stacks may be at any place in the address space, allowing a
heap-allocated env parameter to fail the check.

ok deraadt@, kettenis@, guenther@ at least

zap rcsid.
okay deraadt@ (tested them all)

Remove the advertising clause in the UCB license which Berkeley
rescinded 22 July 1999. Proofed by myself and Theo.

reversed condition checking for sig*jmp(, savemask)

deal w/ longjmp(, 0)

fix typo, and put back stack frame ops

reverse condition in the sp botchness check, we need to nullify
if we are ok not if we are bad. fix a pasto in branch w/in longjmps.

implement the setjmp/longjmp family, based on fredette@'s work