Open Screen Library supports cross compilation using the target_cpu GN argument. Since we use the same build tooling as the Chromium project, most cross compiling scenarios supported in Chrome should also be supported in Open Screen, at least for platforms that have a proper platform/ implementation.
Setting an arm/arm64 target_cpu causes GN to download a sysroot image from Chrome's public cloud storage bucket. This image is referenced by GN when building using the compiler --sysroot flag. This allows the compiler to effectively cross compile for different architectures.
Sysroot versions are maintained upstream in Chromium. Updates flow into Open Screen through rolls to the DEPS/gclient files for the build/ directory.
To run executables on an embedded device, after copying the relevant binaries you may need to install additional dependencies, such as libavcodec and libsdl. For a list of these packages specifically for cast streaming, see the external libraries.md documentation.