mcc with -l option will create a C shared library and it's not .NET.
This document describes how to create .NET Assembly by mcc command. You need to add -W option.
mcc -W dotnet:assembly_name,className,framework_version,security,remote_type -T link:lib options mfilename1,...,mfilenameN
mcc -W dotnet:assembly_name,className,framework_version,security,remote_type -T link:lib options class{className:mfilename1,...,mfilenameN}
For exmaple,
mcc -W 'dotnet:dotNetSample,Class1,4.5,private' -T link:lib -v dotNetSample.m
will create .NET 4.5 libraries (dotNetSample.dll and Class1.cs and so on) from dotNetSample.m.
