Can't build with RelWithDebInfo

[felixf4xu]

If I build with colcon ... -DCMAKE_BUILD_TYPE=RelWithDebInfo, there is a build error:

--- stderr: rmw_ecal_proto_cpp
CMake Error in CMakeLists.txt:
  IMPORTED_LOCATION not set for imported target "rmw::rmw" configuration
  "RelWithDebInfo".

I have to use -DCMAKE_BUILD_TYPE=Release to pass building.