[sr-dev] git:4.1: modules/sdpops: added sdp_with_transport_like() function

while doing it, i noticed that several modules use memmem or ser_memmem function. memmem is built in, but requires #define _GNU_SOURCE it is used by auth_identity module. nathelper, rtpengine, and rttproxy modules (and now also sdpops) as well as parser use ser_memmem and each defines it separately. what is the preferred way to straighten out this mess? can we assume that kamailio code is non-portable and thus defining _GNU_SOURCE is acceptable. if not, what is the best place to put ser_memmem so that it is defined only once? -- juha