anchor.diff:    };
   
     buildInputs =
  -    [ cmake boost libunwind mariadb libmemcached pcre libevent gd curl
  +    [ cmake pkgconfig boost libunwind mariadb libmemcached pcre libevent gd curl
         libxml2 icu flex bison openssl zlib php expat libcap oniguruma
         libdwarf libmcrypt tbb gperftools bzip2 openldap readline
         libelf uwimap binutils cyrus_sasl pam glog libpng libxslt ocaml
  
positive.code: { stdenv, fetchgit, cmake, boost, libunwind, mariadb, libmemcached, pcre
  , libevent, gd, curl, libxml2, icu, flex, bison, openssl, zlib, php, re2c
  , expat, libcap, oniguruma, libdwarf, libmcrypt, tbb, gperftools, glog
  , bzip2, openldap, readline, libelf, uwimap, binutils, cyrus_sasl, pam, libpng
  , libxslt, ocaml
  }:
  
  stdenv.mkDerivation rec {
  
negative.code:   USE_HHVM=1;
    MYSQL_INCLUDE_DIR="${mariadb}/include/mysql";
    MYSQL_DIR=mariadb;
  
    # work around broken build system
    NIX_CFLAGS_COMPILE = "-I${freetype}/include/freetype2";
  
    patchPhase = ''
      substituteInPlace hphp/util/generate-buildinfo.sh \
  