Building

The output is build/lodestone_client.dll (the client, injected into Minecraft) and build/lodestone-inject.exe (the loader). Both are 64-bit Windows binaries, built with the mingw-w64 g++ toolchain. You need three things whichever OS you build on:

1. mingw-w64 g++ (provides x86_64-w64-mingw32-g++ and …-gcc)
2. GNU make
3. A JDK's include directory — for jni.h. Any JDK 17+ works; the client targets Minecraft 26.2's JDK 25.

Then point JAVA_INC at that JDK include directory and run make.

Windows

Do not run make from cmd.exe with a bare mkdir/rm — this Makefile now handles cmd, but the simplest path is one of:

MSYS2 (recommended)

pacman -S mingw-w64-x86_64-toolchain make

Open the MINGW64 shell and, from the project directory:

make CXX=g++ CC=gcc OBJDUMP=objdump \
     JAVA_INC="/c/Program Files/Java/jdk-25/include"

(In the MINGW64 environment the compiler is simply g++.)

WinLibs + a standalone make, from cmd.exe

Put WinLibs' bin on your PATH (it ships x86_64-w64-mingw32-g++.exe), then:

make JAVA_INC="C:/Program Files/Java/jdk-25/include"

Use forward slashes in the path even on Windows.

Linux (cross-compile)

sudo apt install g++-mingw-w64-x86-64 make    # Debian/Ubuntu
make JAVA_INC=/path/to/jdk/include

Checking the result

The DLL must depend on only KERNEL32, USER32, GDI32, OPENGL32 and msvcrt — never libstdc++-6.dll, or it will fail to inject with "a dependency is missing". On Linux the build prints this list; anywhere, check it with:

x86_64-w64-mingw32-objdump -p build/lodestone_client.dll | grep "DLL Name"