E2SM-RC RRC message forwarding (e.g., to signal a new UE, measurement
reports, ...) was broken since commit d6c29b2d2c, as we accidentally
removed the E2_AGENT compilation definition from RRC layer.
Although this commit fixes the mentioned issue, it also causes undefined
references to functions defined in ran_func_rc.c file. Therefore, we
add a hack that provides the definition, and abort if we ever hit these
functions, which in theory should not happen.
Future cleanup should avoid linking in RRC and other layers into
simulators.
Fixes: d6c29b2d2c ("Fix E2_AGENT linking w.r.t. simulators ")
Robert Schmidt
388ad30f6b