It appears that dlopen/dlsym/dlclose are now available from within libc itself, thus these DllImport statements end up failing because there's no longer a libdl.so being shipped.
https://github.com/ReClassNET/ReClass.NET/blob/master/ReClass.NET/Native/NativeMethods.Unix.cs#L13-L19
Changing these to just "libc" will get it running again in a pinch.
Trace for good measure:
System.DllNotFoundException: libdl.so assembly:<unknown assembly> type:<unknown type> member:(null)
at (wrapper managed-to-native) ReClassNET.Native.NativeMethodsUnix.dlopen(string,int)
at ReClassNET.Native.NativeMethodsUnix.LoadLibrary (System.String fileName) [0x00001] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Native.NativeMethods.LoadLibrary (System.String name) [0x00001] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Core.InternalCoreFunctions.Create () [0x00021] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Core.CoreFunctionsManager..ctor () [0x00013] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Program.Main (System.String[] args) [0x000f0] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
[ERROR] FATAL UNHANDLED EXCEPTION: System.DllNotFoundException: libdl.so assembly:<unknown assembly> type:<unknown type> member:(null)
at (wrapper managed-to-native) ReClassNET.Native.NativeMethodsUnix.dlopen(string,int)
at ReClassNET.Native.NativeMethodsUnix.LoadLibrary (System.String fileName) [0x00001] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Native.NativeMethods.LoadLibrary (System.String name) [0x00001] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Core.InternalCoreFunctions.Create () [0x00021] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Core.CoreFunctionsManager..ctor () [0x00013] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
at ReClassNET.Program.Main (System.String[] args) [0x000f0] in <d7d91109515a4cd2b6ef1c0a31e9deed>:0
It appears that dlopen/dlsym/dlclose are now available from within libc itself, thus these DllImport statements end up failing because there's no longer a libdl.so being shipped.
https://github.com/ReClassNET/ReClass.NET/blob/master/ReClass.NET/Native/NativeMethods.Unix.cs#L13-L19
Changing these to just "libc" will get it running again in a pinch.
Trace for good measure: