diff --git a/testing/rust/build b/testing/rust/build
index 60dfdce5..7eefaffe 100755
--- a/testing/rust/build
+++ b/testing/rust/build
@@ -41,5 +41,10 @@ EOF
 
 DESTDIR="$1" ./x.py install -v
 
-python3 ./x.py build
+python3 ./x.py build -j "$(nproc)"
 DESTDIR="$1" python3 ./x.py install
+
+# Remove junk.
+rm -rf "$1/etc/bash_completion.d"
+rm -rf "$1/usr/share/zsh"
+rm -rf "$1/usr/share/doc"