GNU Make. A version of GCC or Clang that supports C++11. pkg-config to locate dependencies. If your distribution does not provide it, you can get it from . The OpenSSL library to calculate cryptographic hashes. If your distribution does not provide it, you can get it from . The bzip2 compressor program and the libbz2 library. Thus you must have bzip2 installed, including development headers and libraries. If your distribution does not provide these, you can obtain bzip2 from . The SQLite embedded database library, version 3.6.19 or higher. If your distribution does not provide it, please install it from . The Boehm garbage collector to reduce the evaluator’s memory consumption (optional). To enable it, install pkgconfig and the Boehm garbage collector, and pass the flag --enable-gc to configure. The xmllint and xsltproc programs to build this manual and the man-pages. These are part of the libxml2 and libxslt packages, respectively. You also need the DocBook XSL stylesheets and optionally the DocBook 5.0 RELAX NG schemas. Note that these are only required if you modify the manual sources or when you are building from the Git repository. Recent versions of Bison and Flex to build the parser. (This is because Nix needs GLR support in Bison and reentrancy support in Flex.) For Bison, you need version 2.6, which can be obtained from the GNU FTP server. For Flex, you need version 2.5.35, which is available on SourceForge. Slightly older versions may also work, but ancient versions like the ubiquitous 2.5.4a won't. Note that these are only required if you modify the parser or when you are building from the Git repository.