Merge pull request #62 from ids1024/extrautils-lzma

Make extrautils have xz as a build depend

recipes/extrautils/recipe.sh

 GIT=https://github.com/redox-os/extrautils.git
+BUILD_DEPENDS=xz
+export PKG_CONFIG_ALLOW_CROSS=1
+export PKG_CONFIG_PATH=
+export PKG_CONFIG_LIBDIR="$PWD/sysroot/lib/pkgconfig"
+export PKG_CONFIG_SYSROOT_DIR="$PWD/sysroot"