docs: Add xvfb to build deps

Reported-by: Matthew Vernon <matthewv@chiark.greenend.org.uk>
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/docs/build.rst b/docs/build.rst
index 964dfec29b4147f76c9fc1cfeb47e6be0479d740..06a6d6e4bdca163d24cc479c16dea44cf24c48f2 100644 (file)
--- a/docs/build.rst
+++ b/docs/build.rst
@@ -22,7 +22,7 @@ Setup
 
      sudo apt install build-essential cpio git curl moreutils \
                       pkg-config libssl-dev             \
-                      node-typescript inkscape bubblewrap \
+                      node-typescript inkscape bubblewrap xvfb \
                       netpbm imagemagick libtoml-parser-perl \
                       potrace                                \
                       python3-sphinx python3-recommonmark