rfbInitClient segmentation fault on macOS native builds

[changkun]

Describe the bug
segmentation fault exit, debug shows the error hanppens in between of

    if (vnc_settings->encodings)
        rfb_client->appData.encodingsString = strdup(vnc_settings->encodings);

and

    if (rfbInitClient(rfb_client, NULL, NULL)) {

which means it is because of the rfbInitClient. Not sure why.

To Reproduce
Steps to reproduce the behavior:

1. build occamy natively on vnc branch
2. run occamyd
3. access web client
4. connect to vnc container
5. see the error

Expected behavior
connect normally

Desktop (please complete the following information):

• OS: macOS
• Browser chrome