support for nonblocking sockets?

[johnnyhh]

We've been using can_sock_drv.erl in a context where the can network can become disconnected, which causes the write() call in can_sock_drv.c to block before we can restart the interface after detecting a BUS_OFF error frame. Adding the O_NONBLOCK flag to the socket in can_sock_drv_start fixes this issue. Saw some EAGAINs in the code, so it seems like at some point you considered using nonblocking sockets? Did you come across any problems with implementing nonblocking sockets that stopped you from using them?

[tonyrog]

Hi! I think the part of the code is from regular sockets that was nonblocking and when the code was adopted to CAN sockets I assumed that blocking was not an issue. But I am happy to accept a pull request. Thanks.

[tonyrog]

Ping?