Merge branch 'rollback-bad-xz-changes' into 'master'

Fix broken xz recipe

See merge request redox-os/cookbook!247

recipes/xz/recipe.toml

 [source]
 tar = "https://codeload.github.com/xz-mirror/xz/tar.gz/v5.2.5"
+script = """
+./autogen.sh
+"""
 
 [build]
 template = "custom"