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

Adapt SYS.h to use retguard macros from asm.h, so that generated system
calls are guarded. Adapt the first few hand-written functions to this
model (a few remain)
ok kettenis mortimer

The 2nd and 3rd argument are pointers, so use the appropriate doubleword
instructions.

ok drahn@

Avoid "bare" register numbers.

PowerPC64 libc powerpc sys files
Initial attempt to port powerpc code to powerpc64

Expects TOC loading in ENTRY(),

ok kettenis@ (some cleanup required)

Adapt SYS.h to use retguard macros from asm.h, so that generated system
calls are guarded. Adapt the first few hand-written functions to this
model (a few remain)
ok kettenis mortimer

The 2nd and 3rd argument are pointers, so use the appropriate doubleword
instructions.

ok drahn@

Avoid "bare" register numbers.

PowerPC64 libc powerpc sys files
Initial attempt to port powerpc code to powerpc64

Expects TOC loading in ENTRY(),

ok kettenis@ (some cleanup required)

The 2nd and 3rd argument are pointers, so use the appropriate doubleword
instructions.

ok drahn@

Avoid "bare" register numbers.

PowerPC64 libc powerpc sys files
Initial attempt to port powerpc code to powerpc64

Expects TOC loading in ENTRY(),

ok kettenis@ (some cleanup required)