Accessing ring 0 mode from user applications ( and why Borland allows this )

As the semester's deadlines approach, I decided to start working on a project in Operating Systems course at my college. The problem with the project assignment is that it requires students to develop a user application (exe) that will execute as a simple kernel ( basic process and thread management ).

First thing that popped to my mind was : How the hell am I supposed to execute privileged code in user application?

After consulting with other students ( who did the project on time ), I learned that they were able to execute privileged code without problems using Borland 3.1 compiler. However, none of them found that weird nor knew why that worked. Why ( better question here would be how ) does Borland do this? Doesn't this violate fundamental principles of OS security?

Note: I added C++ tag because the project is supposed to be written as a C++ application, with most of the privileged code executed as inline assembly.

Update My question was somewhat poorly phrased originally. Of course I was able to compile code with privileged instructions with any compiler - running the code was the problem.

Two things:

1. Back in the days of 8086 real mode there were no privilege levels. Borland 3.1 was a 16-bit compiler. If you're running code it produces on a 32-bit version of Windows NT, it will run in Virtual 8086 mode using the NTVDM, which also has no privilege levels.

2. Even when using a modern compiler / assembler, it generally won't complain about privileged instructions even in protected mode and long mode. This source code compiles just fine for me in MSVC 2015 but crashes whenever I run it because it tries to access a register that is off-limits to user-mode applications:

int  main()
{
    __asm
    {
        mov eax, cr0
    }
    return 0;
}