diff --git a/ci/ubuntu-install-packages b/ci/ubuntu-install-packages
index b372e0e4..c66fd380 100755
--- a/ci/ubuntu-install-packages
+++ b/ci/ubuntu-install-packages
@@ -1,6 +1,16 @@
 #!/bin/sh
 
+# This script gets run in weird environments that have been stripped of just
+# about every inessential thing. In order to keep this script versatile, we
+# just install 'sudo' and use it like normal if it doesn't exist. If it doesn't
+# exist, we assume we're root. (Otherwise we ain't doing much of anything
+# anyway.)
+if ! command -V sudo; then
+  apt-get update
+  apt-get install -y --no-install-recommends sudo
+fi
 sudo apt-get update
 sudo apt-get install -y --no-install-recommends \
   asciidoctor \
-  zsh xz-utils liblz4-tool musl-tools
+  zsh xz-utils liblz4-tool musl-tools \
+  brotli zstd