Unite all nitems copies in ld.so/util.h

OK deraadt

Prep .c files for removing the #includes from */archdep.h
* replace #include "archdep.h" with #includes of what is used, pulling in
"syscall.h", "util.h", and "archdep.h" as needed
* delete #include <sys/syscall.h> from syscall.h
* only pull in <sys/stat.h> to the three files that use _dl_fstat(),
forward declare struct stat in syscall.h for the others
* NBBY is for <sys/select.h> macros; just use '8' in dl_printf.c
* <machine/vmparam.h> is only needed on i386; conditionalize it
* stop using __LDPGSZ: use _MAX_PAGE_SHIFT (already used by malloc.c)
where necessary
* delete other bogus #includes, order legit per style: <sys/*> then
<*/*>, then <*>, then "*"

dir.c improvement from jsg@
ok and testing assistance deraadt@

Make lazy binding work on riscv64.

prompted by deraadt@

riscv64 ld.so
derived from arm64
go ahead deraadt@

Prep .c files for removing the #includes from */archdep.h
* replace #include "archdep.h" with #includes of what is used, pulling in
"syscall.h", "util.h", and "archdep.h" as needed
* delete #include <sys/syscall.h> from syscall.h
* only pull in <sys/stat.h> to the three files that use _dl_fstat(),
forward declare struct stat in syscall.h for the others
* NBBY is for <sys/select.h> macros; just use '8' in dl_printf.c
* <machine/vmparam.h> is only needed on i386; conditionalize it
* stop using __LDPGSZ: use _MAX_PAGE_SHIFT (already used by malloc.c)
where necessary
* delete other bogus #includes, order legit per style: <sys/*> then
<*/*>, then <*>, then "*"

dir.c improvement from jsg@
ok and testing assistance deraadt@

Make lazy binding work on riscv64.

prompted by deraadt@

riscv64 ld.so
derived from arm64
go ahead deraadt@

Make lazy binding work on riscv64.

prompted by deraadt@

riscv64 ld.so
derived from arm64
go ahead deraadt@

riscv64 ld.so
derived from arm64
go ahead deraadt@