MinGW32 MSVCRT Toolchain

cross-compiler toolchain using MSVCRT as default runtime. Default target: i586-w64-mingw32. Optional overlay: i686-w64-mingw32.

Ideal for compiling binaries compatible with Windows 95/98/ME, 2000, XP and other old systems, avoiding UCRT, while allowing SSE2 and AVX for modern CPUs when desired.

🎯 Objective

Build a clean and minimalist MinGW32 toolchain with:

• binutils
• gcc (phase 1)
• mingw-w64 headers
• mingw-w64 CRT (with MSVCRT)
• gcc (phase 2 - according to mingw32 to make Toolchains or Canadian Cross, is necessary to make GCC in two phases)
• mingw-w64 tools (gendef, genidl, genpeimg, widl)

Supports:

• Legacy Windows (95/98/ME/NT4/2000/XP)
• Modern CPU features (SSE2, AVX) for newer systems, selectable per-project.

✅ Prerequisites

• Linux with:
• wget, tar, make, gcc, gawk, bison, flex, texinfo
• Isolated environment (chroot, container, etc) recommended
• Permissions to install in /opt (or adjust the PREFIX variable)

🛠️ How to use

prepare a CHROOT development environment so that your new toolchain does not have problems with your current environment (which probably already has a toolchain) as this can cause problems, to make a clean toolchain, you MUST create a clean development environment in CHROOT or Docker (if you know how to create one)

Below are brief instructions for creating a CHROOT environment in Arch Linux, but this can be reproduced in any distro of your choice, just create the CHROOT according to your distro

1 - install the devtools package (if it is not already installed)

sudo pacman -S devtools

2 - Create the CHROOT directory wherever you want (I recommend it to be in the HOME folder)

mkdir -p ~/chroot/mingw-root

3 - Create the clean environment in CHROOT (the command will already install the base tools and git inside the CHROOT, include something if necessary) (if you wish)

sudo mkarchroot ~/chroot/mingw-root/root base-devel git

4 - Enter your new isolated environment

sudo arch-nspawn ~/chroot/mingw-root/root

5 - Inside the CHROOT install the extra dependencies

pacman -Syu --noconfirm \
gcc binutils gmp mpfr mpc zlib isl git \
mingw-w64-headers mingw-w64-crt \
make autoconf automake texinfo

6 - Clone this repository

git clone https://github.com/LuizRafael79/mingw32-msvcrt

Prepare the script for use

prepare and execute compile-mingw.sh with:

chmod +x compile-mingw.sh
./compile-mingw.sh

🧪 Post-build

Add to PATH:

export PATH=$PREFIX/bin:$PATH
edit accordingly your PREFIX configuration

⚡ Using the Compiler:

Legacy-safe builds (Win9x/98/ME/NT4) - default, nothing special - perfect for retro:

i586-w64-mingw32-gcc main.c -o main.exe

Win2000+:

i586-w64-mingw32-gcc main.c -o main.exe -DWINVER=0x500 -D_WIN32_WINNT=0x500

WinXP+"

i586-w64-mingw32-gcc main.c -o main.exe -DWINVER=0x501 -D_WIN32_WINNT=0x501

Enable SSE2 (Pentium 4+):

i586-w64-mingw32-gcc main.c -o main.exe -msse2 -mfpmath=sse

(Will not run on 9x/NT4-era hardware.)

Enable AVX (Sandy Bridge+ and OS support):

i586-w64-mingw32-gcc main.c -o main.exe -mavx

AVX needs an OS that saves/restores YMM state. Windows XP does not; think Windows 7 SP1+.

C++ small/static Runtime if desired:

i586-w64-mingw32-g++ main.cpp -o main.exe -static-libgcc -static-libstd++

i686 overlay builds:

i686-w64-mingw32-gcc main.c -o main.exe

Uses --with-arch=pentiumpro internally for i686 optimizations

Example with Legacy flags:

i586-w64-mingw32-gcc -nostdlib -static-libgcc -lmingw32 hello.c -o hello.exe

🖼️ Compatibility

• Generate code for Windows 95/98/ME/2k/XP
• Compatible with Windows NT4/2000/XP
• Don't Work with UCRT (but you have to test it)
• Works with MSVCRT (tested)

📄 License

This project only automates compilations of GNU tools under their respective licenses (GPL/LGPL/BSD).

📄 Note

This repository is part of a complex project comming soon early

🗂️ Feature Matrix

Target Windows	Compiler Flag	CPU Features	Notes
Windows 95/98/ME	i586-w64-mingw32-gcc	Pentium / MMX	Legacy safe
Windows NT4/2000	-DWINVER=0x0500 -D_WIN32_WINNT=0x0500	SSE optional	Modern CPUs can enable SSE2
Windows XP	-DWINVER=0x0501 -D_WIN32_WINNT=0x0501	SSE2 default	Works on most XP-era CPUs
Windows 7+	-DWINVER=0x0601 -D_WIN32_WINNT=0x0601	SSE2 / AVX optional	Enable AVX with -mavx
Modern CPUs	-msse2 -mavx	SSE2 / AVX	Only for CPUs that support it, may break legacy Windows

TODO

• A Canadian Cross that generate Win32 Mingw32 with these options and...
• A Canadian Cross that the same for... MacOS (yeah, virtually impossible but...)
• Update average use of AVX/AVX2/SSE2/3/4 for Windows 9x/NT/2K/XP for use with Kernel mods and others hacks