Use of -rdynamic linker flag?

[traversaro]

On Linux and macOS, this https://github.com/robotology/diagnostic-daemon/blob/master/CMakeLists.txt#L71 passes explicitly the -rdynamic option to the linker. What is the rationale for this? If this is not needed, probably we could remove it to avoid problems such as robotology/robotology-superbuild#649 (comment) .