anchor.diff:      })
     ];
   
  +  postPatch =
  +    # Do not hardcode the include path for libmysqlclient.
  +    ''
  +      substituteInPlace configure \
  +        --replace '-I/usr/include/mysql' '$(mysql_config --include)'
  +    '';
  +
     doCheck = true;
   
     meta = {
  
positive.code: { stdenv
  , fetchurl
  , fetchpatch
  # Excerpt from glpk's INSTALL file:
  # This feature allows the exact simplex solver to use the GNU MP
  # bignum library. If it is disabled, the exact simplex solver uses the
  
negative.code:     sha256 = "040sfaa9jclg2nqdh83w71sv9rc1sznpnfiripjdyr48cady50a2";
    };
  
    buildInputs =
      [ libmysqlclient
      ] ++ stdenv.lib.optionals withGmp [
        gmp
      ];
  
    configureFlags = stdenv.lib.optionals withGmp [
      "--with-gmp"
  