I need to create a NPM package containing a package for Unity. I need to use native code, i. e. a native library. The package needs to support:

• Windows x86 64bit
• Linux x86 64bit
• Embedded Linux ARM

I have written the code for the three native libraries and the C# glue code. Each library is in its own subdirectory inside of the package folder structure and Unity has generated a meta file each time. I. e., I have

    <package root>/
    ├── package.json
    ├── README.md
    ├── (other files)
    └── assets/
        ├── Runtime.meta
        └── Runtime/
            └── Plugins/
                ├── arm.meta
                ├── arm/
                │   ├── libConnect.so
                │   └── libConnect.so.meta
                ├── linux.meta
                ├── linux/
                │   ├── libConnect.so
                │   └── libConnect.so.meta
                ├── windows.meta
                └── windows/
                    ├── Connect.DLL
                    └── Connect.DLL.meta

Depending on the platform I build for, I’d like Unity to use the appropriate native library.

However, I can’t seem to set the properties on the native libs to the right values using the Unity Inspector on the libraries. In particular, I cannot seem to set the Embedded Linux ARM lib to ARM CPU without the Linux lib also changing to ARM CPU. Vice versa, changint the Linux lib to “Intel 64-bit” CPU also sets the Embedded Linux ARM lib to that CPU. Also, the windows DLL always seems to end up in Embedded Linux builds, no matter what settings I use. I tried in- and excluding different platforms for different libs, but still, changes to one lib seem to magically mess up changes I made to the other libs.

Please tell me how I can achive my goal, to have three native libs for different platforms and have Unity use the right one depending on which platform I build for.