Aarch64 support for truss

[kib]

Test Plan

truss ls

mmap(0x0,32768,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANON,-1,0x0) = 1078124544 (0x4042e000)
issetugid() = 0 (0x0)
lstat("/etc",{ mode=drwxr-xr-x ,inode=1123584,size=2048,blksize=32768 }) = 0 (0x0)
lstat("/etc/libmap.conf",{ mode=-rw-r--r-- ,inode=1123621,size=102,blksize=32768 }) = 0 (0x0)
openat(AT_FDCWD,"/etc/libmap.conf",O_CLOEXEC,00) = 3 (0x3)
fstat(3,{ mode=-rw-r--r-- ,inode=1123621,size=102,blksize=32768 }) = 0 (0x0)
mmap(0x0,102,PROT_READ,MAP_PRIVATE,3,0x0) = 1078157312 (0x40436000)
close(3) = 0 (0x0)
lstat("/usr",{ mode=drwxr-xr-x ,inode=401280,size=512,blksize=32768 }) = 0 (0x0)
lstat("/usr/local",{ mode=drwxr-xr-x ,inode=401287,size=512,blksize=32768 }) = 0 (0x0)
lstat("/usr/local/etc",{ mode=drwxr-xr-x ,inode=483268,size=512,blksize=32768 }) = 0 (0x0)
lstat("/usr/local/etc/libmap.d",0x7fffffdbc0) ERR#2 'No such file or directory'
munmap(0x40436000,102) = 0 (0x0)
openat(AT_FDCWD,"/var/run/ld-elf.so.hints",O_CLOEXEC,00) = 3 (0x3)
read(3,"Ehnt\^A\0\0\0\M^@\0\0\0-\0\0\0\0"...,128) = 128 (0x80)
lseek(3,0x80,SEEK_SET) = 128 (0x80)

[kib]

Per emaste request, remov Fagan' copyright and clauses 3,4.

Fix SYS_syscall handling.

I think that the kernel code mis-handles 8-args syscalls done through SYS_syscall, by failing to fetch the arg 8 from the stack. The truss follows kernel currently. I am not sure that we have such 8-args syscall,

git grep -e n_args -- sys/kern/systrace_args.c | grep 8

does not show any output.

[jhb]

You beat me to it. :)

usr.bin/truss/aarch64-fbsd.c

45 ↗

(On Diff #8996)

I plan on doing a sweep to fix this warning in all the backends, but my plan was to just put 'static' before the #include.