We really don't want this in gst-plugins-bad because of legal complexities around RTMP and possible problems for distributions. Add README that explains how to build librtmp to be suitable for linking to the GStreamer plugin.
rtmpsrc: This plugin requires librtmp from http://rtmpdump.mplayerhq.hu/ You have to build librtmp with -fPIC to be able to use it with the GStreamer plugin: make XCFLAGS="-fPIC"