.github: add CI pipeline

This pipeline builds the driver against the latest Xserver stable
release as well as current master.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

.github/scripts/install-prereq.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+set -e
+
+. .github/scripts/util.sh
+
+mkdir -p $X11_BUILD_DIR
+cd $X11_BUILD_DIR
+
+if [ "$X11_OS" = "Linux" ]; then
+build_meson   drm               https://gitlab.freedesktop.org/mesa/drm                  libdrm-2.4.121   "" \
+    -Domap=enabled
+fi
+build_meson   libxcvt           https://gitlab.freedesktop.org/xorg/lib/libxcvt          libxcvt-0.1.0
+build_ac      xorgproto         https://gitlab.freedesktop.org/xorg/proto/xorgproto      xorgproto-2024.1