This repo contains makefiles and support files that allow you to build Descent 1 for DOS. It uses a binextr utility to extracts the necessary external libraries from an existing descentr.exe that you'll need to provide. It also contains a few patches the source code to make it equal to the Descent 1.5 exe.
The only differences in the resulting exe are different uninitialized padding bytes between strings and a different order for the relocation metadata.
You'll need Watcom 9.5b, MASM 6.11, the Descent 1.5 exe and a DOS(Box)/Win32/wine environment. For wine, patch wlink.exe with this patch.
The Descent exe must be copied to the original directory.
Start compilation with wmake in the top directory.