/nostdlib (C# Compiler Options)
/nostdlib prevents the import of mscorlib.dll, which defines the entire System namespace.
/nostdlib[+ | -]
Remarks
Use this option if you want to define or create your own System namespace and objects.
If you do not specify /nostdlib, mscorlib.dll will be imported into your program (same as specifying /nostdlib-). Specifying /nostdlib is the same as specifying /nostdlib+.
To set this compiler option in the Visual Studio development environment
Open the Properties page for the project.
Click the Build properties page.
Click the Advanced button.
Modify the Do not reference mscorlib.dll property.
For information on how to set this compiler option programmatically, see NoStdLib.