gen_rpc_util to check otp_release and set default_tcp_opt
move DEFAULT_TCP_OPTS in header to share
Remark:
The actual version check of an OTP release is recommended to be done through file reads: http://www.erlang.org/doc/system_principles/versions.html
But reltool doesn't generate these files for example. OTP release does not guarantee that options exists (older versions of kernel or inet for whatever reasons).
The reason this version check is being done is for a simple TCP option so the current implementation is good enough. Also, I would have named the util module gen_rpc_helpers. Great work!
Remark: The actual version check of an OTP release is recommended to be done through file reads: http://www.erlang.org/doc/system_principles/versions.html But reltool doesn't generate these files for example. OTP release does not guarantee that options exists (older versions of kernel or inet for whatever reasons).