cooker, seitan: simple working example

parser:
  - add OP_BLOCK and OP_RETURN to the parser
seitan:
  - fix op_cmp in seitan, it was jmp when comparison was true

Working example:
demo.json:
[
  {
    "match": [ /* qemu-pr-helper and similar */
      { "connect": { "addr": { "family": "unix", "path": "/tmp/test.sock" } } }
    ],
    "return": 0
  }
]

Create gluten and the bpf filter:
$ seitan-cooker demo.hjson demo.gluten demo.bpf

Launch the seitan eater with the target program:
$ seitan-eater -i demo.bpf -- strace -e connect tests-utils/test-syscalls connect

Start seitan with gluten:
$ seitan -i demo.gluten -p $(pgrep seitan-eater)

Seitan mocks the connect syscall and `connect` returns successfully:
$ seitan-eater -i demo.bpf -- strace -e connect tests-utils/test-syscalls connect
Test syscall: connect
connect(4, {sa_family=AF_UNIX, sun_path="/tmp/test.sock"}, 108) = 0

1 files changed, 1 insertions, 1 deletions

diff --git a/operations.h b/operations.h
index 9d017e0..b1d0ac2 100644
--- a/operations.h
+++ b/operations.h
@@ -21,7 +21,7 @@
 			if (res == 0)                                   \
 				(op)++;                                 \
 			else if (res == -1)                             \
-				return -1;                            \
+				return -1;                              \
 			else                                            \
 				(op) += res;                            \
 		} while (0);                                            \