You must be running a 64-bit x86 Linux distribution. Darling cannot be used on a 32-bit x86 system, not even to run 32-bit applications.

It is recommended that you use at least Clang 3.8. You can force a specific version of Clang (if it is installed on your system) by editing Toolchain.cmake.

Linux 4.9 and higher is required.

sudo apt install cmake clang bison flex xz-utils libfuse-dev libudev-dev pkg-config libc6-dev-i386 linux-headers-amd64 libcap2-bin git libgcc-5-dev:i386 libcairo2-dev libgl1-mesa-dev libtiff5-dev libfreetype6-dev libfreetype6-dev:i386 libxml2-dev libegl1-mesa-dev libfontconfig1-dev libbsd-dev

sudo apt install cmake clang-4.0 bison flex xz-utils libfuse-dev libudev-dev pkg-config libc6-dev-i386 linux-headers-amd64 libcap2-bin git libcairo2-dev libgl1-mesa-dev libtiff5-dev libfreetype6-dev libxml2-dev libegl1-mesa-dev libfontconfig1-dev libbsd-dev

sudo apt-get install cmake clang bison flex xz-utils libfuse-dev libudev-dev pkg-config libc6-dev:i386 linux-headers-generic gcc-multilib libcap2-bin libcairo2-dev libgl1-mesa-dev libtiff5-dev libfreetype6-dev libfreetype6-dev:i386 git libelf-dev libxml2-dev libegl1-mesa-dev libfontconfig1-dev libbsd-dev

sudo pacman -S --needed make cmake clang flex bison icu fuse linux-headers gcc-multilib lib32-gcc-libs pkg-config fontconfig cairo libtiff python2 mesa

sudo dnf install cmake clang bison flex python2 glibc-devel.i686 fuse-devel systemd-devel kernel-devel elfutils-libelf-devel cairo-devel freetype-devel.{x86_64,i686} libjpeg-turbo-devel.{x86_64,i686} libtiff-devel.{x86_64,i686} fontconfig-devel.{x86_64,i686} libglvnd-devel mesa-libGL-devel libxml2-devel libbsd-devel

Darling makes extensive use of Git submodules, therefore you cannot use a plain git clone. Make a clone like this:

git clone --recursive https://github.com/darlinghq/darling.git

Now let's build Darling:

# Move into the cloned sources
cd darling

# Make a build directory
mkdir build && cd build

# Configure the build
cmake ..

# Build and install Darling
make
sudo make install

Darling also requires a kernel module named darling-mach:

make lkm
sudo make lkm_install

If module installation produces warnings such as SSL error:02001002:system library:fopen:No such file or directory: bss_file.c:175, then these can be usually ignored, unless you configured your system to enforce secure boot.

The kernel module is an experimental piece of code; it's likely to have many bugs and vulnerabilities. Be prepared for kernel hangups and crashes, and run Darling on a virtual machine if possible.