Add symlinks to uutils package

recipes/uutils/recipe.sh

 GIT=https://github.com/redox-os/uutils.git
 CARGOFLAGS="--no-default-features --features redox"
+
+function recipe_stage {
+    mkdir -p "$1/bin"
+    ln -s uutils "$1/bin/chmod"
+    ln -s uutils "$1/bin/env"
+    ln -s uutils "$1/bin/expr"
+    ln -s uutils "$1/bin/install"
+    ln -s uutils "$1/bin/ls"
+    ln -s uutils "$1/bin/mktemp"
+}