CMake: Option to not build/install the executable ouster_client_example

[vebjornjr]

Hey again.

We build and install this library (ouster_client.a) to a folder in our git repo for full control of versions with regards to deployment and such. In such a case it would be useful with a CMake option to not build the executable since we don't want to commit a executable that we don't use into our repo.

If we delete the binary produced, we get CMake errors from:

find_package(OusterSDK 20220608 EXACT CONFIG REQUIRED
    PATHS
        ${PROJECT_SOURCE_DIR}/../../external
)

-- Found OusterSDK: /media/nvidia/ssd/steer/external/lib/cmake/OusterSDK/OusterSDKConfig.cmake
CMake Error at /media/nvidia/ssd/steer/external/lib/cmake/OusterSDK/OusterSDKTargets.cmake:88 (message):
The imported target "OusterSDK::ouster_client_example" references the file

 "/media/nvidia/ssd/steer/external/bin/ouster_client_example"

but this file does not exist. Possible reasons include:

• The file was deleted, renamed, or moved to another location.

• An install or uninstall procedure did not complete successfully.

• The installation package was faulty and contained

  "/media/nvidia/ssd/steer/external/lib/cmake/OusterSDK/OusterSDKTargets.cmake"

but not all the files it references.

[kairenw]

Yeah, that's not ideal! Thanks for pointing that out. We can probably push out a fix probably this week or next.

Leaving this open till it's addressed. Thanks!

[kairenw]

I believe this is addressed by #420. Closing this out.