mingw-w64-libs

Microsoft's license doesn't permit bundling other prebuilt compilers with their WinSDK & Visual C++ runtime libraries (for linking, i.e., either the static libs or the import libs for the dynamic runtime).

This repository consists of a set of tools to generate import libraries for the Windows and Visual C++ runtime DLLs, intended as drop-in replacement for the official Microsoft import libraries.

The MinGW-w64 runtime is based on custom import libraries for the Microsoft DLLs, but also extends the MS runtime for Posix/GNU compatibility and overrides some functions, e.g., because MinGW uses 80-bit extended precision for long double, whereas Microsoft uses 64-bit double precision.

The generated import libraries here are based on the .def definition files from MinGW-w64, but don't include any MinGW runtime additions. The libraries are built by the buildsdk.d tool; see the top comment in that file for how to use it.

The basic approach is:

1. Patch the MinGW-w64 .def files by trying to undo all MinGW-specific overriding of Microsoft functions.
2. Ignore the aliases in the .def files and instead use verified aliases in the *.aliases{32,64} files. These files have been generated via the extractAliases.d tool, which parses the dumpbin /symbols output of Microsoft .lib files.
3. Generate .lib import libraries based on the patched .def files.
4. Provide a minimal C runtime skeleton in the msvcrt_*.c files, providing the mainCRTStartup / WinMainCRTStartup / _DllMainCRTStartup entry points, invoking the C runtime constructors/destructors, atexit handlers etc. These objects are merged into the generated vcruntime140.lib library (targeting the Visual C++ 2015 runtime) and should be enough for a typical D application.

Evolution of this approach:

• dlang/installer#289
• dlang/installer#346