When you are comfortable with the changes you have made to the OEMDONGL.C source code, it is time to build your version of OEMDONGL.VXD. A MAKEFILE in the DDK subdirectory contains all the directives the compiler, assembler, and linker need to create OEMDONGL.VXD. Before you run the MAKEFILE, you have to match it to your the build environment by carrying out the steps in the following.