Hi all, I'm a maintainer for nixpkgs, the official package repository of the nix[1] package manager, and I've just finished adding the packages that make up the 3.4 release. Overall I am very impressed with your build system (especially given the scope of the project), but there were a few minor issues that I thought you might want to know about in case they can be fixed for future releases. In nixpkgs, we use llvm as a dependency of mesa (for gallium), and so we needed to build llvm and clang separately so as not to require all X users to build clang. In addition, to save space on systems that have more than one package linked to llvm we build it with shared libraries (nix allows us to do this safely even if multiple versions of llvm are installed, see [1] for details). This combination required a few tweaks: * Before running make for llvm, I had to set up a symlink from $prefix/lib pointing to $buildRoot/lib. This is because llvm-tablegen runs during the build, but its rpath points to $prefix/lib * For lld and clang, I had to unpack the llvm source and point *_PATH_TO_LLVM_SOURCE appropriately, despite having a proper llvm install available in *_PATH_TO_LLVM_BUILD. Based on the comments in the cmake file, this should not be necessary * I had to patch[2] llvm's source tree when building clang so that clang-tablegen would not try to build itself in llvm's sources * I had to patch[3] clang-tools-extra to include a cmake library that I guess is normally included by the llvm build There were several other small issues as well: * I had to patch[4] polly, I'm guessing that build was never tested with CMAKE_CXX_FLAGS set (we set it to use -std=c++11) * libc++abi depends on the libc++ source for a header, and libc++ depends on the libc++abi build. Not a full circular dependency but annoying to have to unpack the libc++ sources for the libc++abi build and then again for the libc++ build * libc++abi has a spurious -lstdc++ in its build script, which I patched out (to no ill effect) in order to avoid a dependency on libstdc++ * There is no official release for libc++abi * There are no official installation instructions for libc++abi * It would be nice to be able to build compiler-rt and clang-tools-extra separately from llvm and clang, respectively Anyway, I'm writing this not to complain but to let you know about the issues. If there's any way I can help improve things, please let me know! Cheers, Shea Levy 1: http://nixos.org/nix 2: https://raw.github.com/NixOS/nixpkgs/fea2266/pkgs/development/compilers/llvm/3.4/llvm-separate-build.patch 3: https://raw.github.com/NixOS/nixpkgs/fea2266/pkgs/development/compilers/llvm/3.4/clang-separate-build.patch 4: https://raw.github.com/NixOS/nixpkgs/fea2266/pkgs/development/compilers/llvm/3.4/polly-separate-build.patch