OPTLINK is the Digital Mars linker. It is used by D on Windows to link 32-bit OMF files.
Here is how to build OPTLINK from sources yourself.
1. Clone the OPTLINK sources from GitHub:
git clone https://github.com/DigitalMars/optlink.git cd optlink
2. Put Microsoft's development tools on your PATH:
"[path to Microsoft Visual C/C++]\VC\bin\vcvars32.bat"
"C:\Program Files (x86)\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
3. Put ImageCFG and the DM bin directory on your PATH:
set PATH=[path to ImageCFG];%PATH%;[path to dmc.exe]
4. Ensure everything works:
nmake /? imagecfg
5. Build OPTLINK. Note that [path to Digital Mars tools] should be the directory which contains "bin/dmc.exe", not the bin directory itself:
build_optlink.bat DM=[path to Digital Mars tools]
6. Ensure OPTLINK was built successfully: