user: What would the C source look like for the assembly code provided here?

```asm
<runner_main>:
  endbr64
  push   %r12
  xor    %eax,%eax
  push   %rbp
  sub    $0x8,%rsp
  call   <bitgraph_empty@plt>
  xor    %esi,%esi
  mov    $0x10,%edx
  mov    %eax,%edi
  call   <asserter_crash_if_not_equal@plt>
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  mov    %eax,%ebp
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  xor    %edx,%edx
  xor    %esi,%esi
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  mov    %ebp,%esi
  mov    $0x13,%edx
  mov    %eax,%edi
  call   <asserter_crash_if_equal@plt>
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  xor    %esi,%esi
  mov    $0x1,%edx
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  mov    %eax,%ebp
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  xor    %edx,%edx
  xor    %esi,%esi
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  mov    %ebp,%esi
  mov    $0x14,%edx
  mov    %eax,%edi
  call   <asserter_crash_if_equal@plt>
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  xor    %esi,%esi
  mov    $0x1,%edx
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  mov    %eax,%ebp
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  xor    %edx,%edx
  mov    $0x1,%esi
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  mov    $0x15,%edx
  mov    %ebp,%esi
  mov    %eax,%edi
  call   <asserter_crash_if_equal@plt>
  xor    %eax,%eax
  call   <bitset_empty@plt>
  mov    %eax,%ebp
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  xor    %esi,%esi
  mov    %eax,%edi
  call   <bitgraph_neighbors_get@plt>
  mov    %ebp,%esi
  mov    $0x18,%edx
  mov    %eax,%edi
  call   <asserter_crash_if_not_equal@plt>
  xor    %eax,%eax
  call   <bitset_empty@plt>
  mov    %eax,%ebp
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  xor    %edx,%edx
  xor    %esi,%esi
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  xor    %esi,%esi
  mov    %eax,%edi
  call   <bitgraph_neighbors_get@plt>
  mov    %ebp,%esi
  mov    $0x19,%edx
  mov    %eax,%edi
  call   <asserter_crash_if_equal@plt>
  xor    %eax,%eax
  call   <bitgraph_empty@plt>
  mov    %eax,%r12d
  xor    %eax,%eax
  call   <bitset_empty@plt>
  xor    %edx,%edx
  xor    %esi,%esi
  mov    %r12d,%edi
  mov    %eax,%ebp
  call   <bitgraph_edge_add@plt>
  xor    %esi,%esi
  mov    $0x1,%edx
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  mov    $0x3,%edx
  xor    %esi,%esi
  mov    %eax,%edi
  call   <bitgraph_edge_add@plt>
  xor    %esi,%esi
  mov    %ebp,%edi
  mov    %eax,%r12d
  call   <bitset_add@plt>
  mov    $0x1,%esi
  mov    %eax,%edi
  call   <bitset_add@plt>
  mov    $0x3,%esi
  mov    %eax,%edi
  call   <bitset_add@plt>
  xor    %esi,%esi
  mov    %r12d,%edi
  mov    %eax,%ebp
  call   <bitgraph_neighbors_get@plt>
  mov    %ebp,%esi
  mov    $0x21,%edx
  mov    %eax,%edi
  call   <asserter_crash_if_not_equal@plt>
  add    $0x8,%rsp
  xor    %eax,%eax
  pop    %rbp
  pop    %r12
  ret
```

assistant: ```c
int runner_main(void) {
  asserter_crash_if_not_equal(bitgraph_empty(), 0, 16);
  asserter_crash_if_equal(bitgraph_edge_add(bitgraph_empty(), 0, 0), bitgraph_empty(), 19);
  asserter_crash_if_equal(bitgraph_edge_add(bitgraph_empty(), 0, 0), bitgraph_edge_add(bitgraph_empty(), 0, 1), 20);
  asserter_crash_if_equal(bitgraph_edge_add(bitgraph_empty(), 1, 0), bitgraph_edge_add(bitgraph_empty(), 0, 1), 21);
  asserter_crash_if_not_equal(bitgraph_neighbors_get(bitgraph_empty(), 0), bitset_empty(), 24);
  asserter_crash_if_equal(bitgraph_neighbors_get(bitgraph_edge_add(bitgraph_empty(), 0, 0), 0), bitset_empty(), 25);
  {
    unsigned int graph = bitgraph_empty();
    unsigned int set = bitset_empty();
    graph = bitgraph_edge_add(bitgraph_edge_add(bitgraph_edge_add(graph, 0, 0), 0, 1), 0, 3);
    set = bitset_add(bitset_add(bitset_add(set, 0), 1), 3);
    asserter_crash_if_not_equal(bitgraph_neighbors_get(graph, 0), set, 33);
  }
  return 0;
}
```