This page lists the requirements for running bindgen and how to get them.
bindgen leverages libclang to preprocess, parse, and type check C and C++ header files.
It is recommended to use Clang 3.9 or greater, however bindgen can run with older Clangs with some features disabled.
If you are generating bindings to C, 3.7 and 3.8 will probably work OK for you.
If you are generating bindings to C++, you almost definitely want 3.9 or greater.
Download and install the official pre-built binary from LLVM download page.
You will also need to set LIBCLANG_PATH as an environment variable pointing to the bin directory of your LLVM install. For example, if you installed LLVM to D:\programs\LLVM, then you'd set the value to be D:\programs\LLVM\bin.
Alternatively, for Mingw64, you can install clang via
pacman -S mingw64/mingw-w64-x86_64-clang
If you use Homebrew:
$ brew install llvm
If you use MacPorts:
$ port install clang
# apt install llvm-dev libclang-dev clang
Ubuntu 16.10 provides the necessary packages directly. If you are using older version of Ubuntu or other Debian-based distros, you may need to add the LLVM repos to get version 3.9. See http://apt.llvm.org/.
# pacman -S clang
# dnf install clang-devel
# pkg_add llvm
Add export LIBCLANG_PATH=/usr/local/lib to your profile.
If your package manager doesn‘t yet offer Clang 3.9, you’ll need to build from source. For that, follow the instructions here.
Those instructions list optional steps. For bindgen: