Hi There,
We found a situation where topos seems to break, let me explain... Assuming the
following scenario:
```
Caller Callee
A: --INVITE-> Record-Route:A.A.A.A, Record-Route:B.B.B.B
B: <-200 OK--
C: <-INVITE-- Route: A.A.A.A, B.B.B.B
D: --200 OK->
when using sdp module to parse sdp I noticed that function called from sdp_get
return -1 when no m-lines are present in sdp , normally we should accept sdp
without m -line because it can be at a later time through a modified offer ,
how can we accept such sdp without changing source code for f