GitLab

COmpilation fixes for mingw.

initialize belle_sip_source_t part of channel, otherwise there is a risk of later calling close on fd 0 (which is bad !)

better management of partial SIP message

- always send expires according to the original requirement (unless a 423 is replied by the server)
- schedule a refresh according to the expires provided in the server's response

 - Use size_t instead of unsigned int for offset.
 - Add function to enable marshal check at runtime.
 - Enable marshal check in unit tests.