truss: add ppoll(2) argument decoding

PR:		264029
Approved by:	emaste
MFC after:	3 days

usr.bin/truss/syscalls.c

@@ -422,6 +422,9 @@ static const struct syscall_decode decoded_syscalls[] = {
 		    { Fadvice, 3 } } },
 	{ .name = "posix_openpt", .ret_type = 1, .nargs = 1,
 	  .args = { { Open, 0 } } },
+	{ .name = "ppoll", .ret_type = 1, .nargs = 4,
+	  .args = { { Pollfd, 0 }, { Int, 1 }, { Timespec | IN, 2 },
+ 		    { Sigset | IN, 3 } } },
 	{ .name = "pread", .ret_type = 1, .nargs = 4,
 	  .args = { { Int, 0 }, { BinString | OUT, 1 }, { Sizet, 2 },
 		    { QuadHex, 3 } } },