sstercan/w64devkit

Portable C and C++ Development Kit for x64 Windows

Portable C and C++ Development Kit for x64 Windows

w64devkit is a Dockerfile that builds from source a small, portable development suite for writing C and C++ applications on and for x64 Windows. Docker is not needed to use the tools themselves. It's merely used as reliable, clean environment for compilation and linking. Included tools:

• Mingw-w64 GCC : compilers, linker, assembler
• GDB : debugger
• GNU Make : standard build tool
• busybox-w32 : standard unix utilities, including sh
• Vim : powerful text editor
• Universal Ctags : source navigation
• NASM : x86 assembler

The compilers support pthreads, C++11 threads, and OpenMP. All included libraries are static.

Build

First build the image, then run it to produce a distribution .zip file:

docker build -t w64devkit .
docker run --rm w64devkit >w64devkit.zip

This takes about half an hour on modern systems. You will need an internet connection during the first couple minutes of the build.

Usage

The final .zip file contains tools in a typical unix-like configuration. Unzip the contents anywhere and add its bin/ directory to your path. For example, while inside a console or batch script:

set PATH=c:\path\to\w64devkit\bin;%PATH%

Then to access a small unix environment:

busybox sh -l

This will expose the rest of busybox's commands without further action. However, the unix environment will not be available to other tools such as make without "installing" BusyBox into the bin/ directory:

busybox --install

The distribution contains activate.bat that launches a console window with the path pre-configured and ready to go. It's an easy way to enter the development environment.

Notes

Due to an old GCC bug, we must build a cross-compiler to cross-compile GCC itself because, due to host contamination, GCC can only be correctly and safely cross-compiled by a matching version.

Since the development kit is intended to be flexible, light, and portable — i.e. run from anywhere, in place, and no installation is necessary — the binaries are all optimized for size, not speed.

I'd love to include Git, but unfortunately Git's build system is a disaster and doesn't support cross-compilation. It's also got weird dependencies like Perl. Git may be a fantastic and wonderful tool, but it's also kind of a mess.

It would be nice to have a better shell like Bash. BusyBox's ash is limited, and the Windows port is even more limited and quite quirky. Unfortunately Bash's build system is a total mess and does not support cross-compilation.

Emacs does not support cross-compilation, particularly due to its fragile dumper. There has been a "portable dumper" in the works for years that, once stable, may eventually resolve this issue. Even then, the parts of the build system that target Windows needlessly assumes a very specific environment (msys), and much of Emacs' source very brittle. Besides all that, Emacs is huge and including it would triple the size of the distribution. So Emacs will not be included.

What about sanitizer support? That would be fantastic, but unfortunately libsanitizer has not yet been ported from MSVC to Mingw-w64 (also).

Since the build environment is so stable and predicable, it would be great for the .zip to be reproducible, i.e. builds by different people are bit-for-bit identical. There are multiple reasons why this is not currently the case, the least of which are timestamps in the .zip file.

License Crap

When distributing binaries built using w64devkit, your .exe will include parts of this distribution. For the GCC runtime, including OpenMP, you're covered by the GCC Runtime Library Exception so you do not need to worry about those. However the Mingw-w64 runtime has the usual software license crap and you might need to comply with various BSD-style licenses depending on the functionality used by your program: MinGW-w64 runtime licensing and winpthreads license. To make this easy, w64devkit includes the complete set of licenses in the file COPYING.MinGW-w64-runtime.txt, which should be distributed with your binaries.