ldd command doesn't work in cross-compile

[kh9sd]

in our pi-cross-compile pipeline job, we build the wiringPi library which is a shared library, so it exists outside of the ecs_pi executable

we've had some trouble with this library not being found at runtime, there is a handy Linux tool called ldd that will check the links on an executable [TODO: show example of missing link]. problem is, we can't run it in the Docker cross compiler container, it errors saying that it's not a dynamic executable. we can only check on the actual Pi. if i had to wager, I think it's because of the fact we cross compiling for different OSs and architectures.

• Determine if we can get ldd to run in our Docker container. If not, so be it
• If it does work, use it with a piped grep to check for missing links during a pipeline run