bazel/Dockerfile: add X11/xcb runtime libs for --//:platform=gui

The Qt GUI openroad binary (built with --//:platform=gui) links against
qt-bazel prebuilts, which stub X11 at link time but resolve libX11/libxcb/
libxkbcommon from the system at load time. The slim bazel-ci image ships no
X11 runtime, so every bazel test run against the gui binary dies immediately
at ld.so with:

  openroad: error while loading shared libraries: libX11-xcb.so.1:
  cannot open shared object file: No such file or directory

Install the runtime (non -dev) subset of etc/DependencyInstaller.sh's GUI
xcb package list. This exactly covers the gui openroad binary's direct
NEEDED entries (verified via readelf/ldd); the tcl test suite runs in CLI
mode and needs no X server or QT_QPA_PLATFORM.

This unblocks jenkins-ci#155, which switches `bazelisk test` to the gui
binary to populate the gui cache.

Signed-off-by: SombraSoft <sombrio@sombrasoft.dev>

Author: sombraSoft

bazel/Dockerfile

@@ -33,6 +33,37 @@ RUN apt-get -y update \
       python3-yaml \
       time
 
+# Runtime X11/xcb libraries for the Qt GUI build (--//:platform=gui).
+# Qt itself is hermetic (qt-bazel prebuilts), but the linked openroad binary
+# still resolves libX11/libxcb/libxkbcommon from the system at load time, so
+# without these every test against the gui binary dies at ld.so with
+# "libX11-xcb.so.1: cannot open shared object file". This is the runtime
+# (non -dev) subset of etc/DependencyInstaller.sh's GUI xcb list.
+RUN apt-get -y update \
+    && apt-get -y install --no-install-recommends \
+      libx11-6 \
+      libx11-xcb1 \
+      libsm6 \
+      libice6 \
+      libxcb1 \
+      libxcb-cursor0 \
+      libxcb-icccm4 \
+      libxcb-image0 \
+      libxcb-keysyms1 \
+      libxcb-randr0 \
+      libxcb-render0 \
+      libxcb-render-util0 \
+      libxcb-shape0 \
+      libxcb-shm0 \
+      libxcb-sync1 \
+      libxcb-util1 \
+      libxcb-xfixes0 \
+      libxcb-xkb1 \
+      libdbus-1-3 \
+      libfontconfig1 \
+      libxkbcommon0 \
+      libxkbcommon-x11-0
+
 RUN groupadd -g 9000 user \
     && useradd -u 9000 -g 9000 -m -s /bin/bash user
 USER user