Add handling for libdl.so.2

[trolleyman]

Closes #2 & #18

[trolleyman]

@mellinoe just in case this hasn't been seen

[Trojaner]

An alternative way would be using NativeLibrary.SetDllImportResolver, see https://stackoverflow.com/a/68677109/2475431
However this needs to check if there is already a custom DllImportResolver, in which case it needs to be called first. Also only works with .NET Core 3+

[trolleyman]

@Trojaner I can't find any way to get the existing DllImportResolver, that's why I didn't use that method as I didn't want to mess up any existing DllImportResolver. Searching for GetDllImportResolver only returns one result, and that is a suggestion about maybe adding that function in future. The docs of SetDllImportResolver mention that "The callers of this method should register the resolver for their own assemblies only".