CI: Refactoring and add Linux SSE2 builds

Windows will follow at some point.

scripts/appimage/install-packages.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+
+function retry_command {
+  # Package servers tend to be unreliable at times..
+  # Retry a bunch of times.
+  local RETRIES=10
+
+  for i in $(seq 1 "$RETRIES"); do
+    "$@" && break
+    if [ "$i" == "$RETRIES" ]; then
+      echo "Command \"$@\" failed after ${RETRIES} retries."
+      exit 1
+    fi
+  done
+}
+
+# Workaround for https://github.com/actions/runner-images/issues/675
+retry_command wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+retry_command sudo apt-add-repository -n 'deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-17 main'
+
+retry_command sudo apt-get update
+retry_command sudo apt-get -y install \
+  build-essential clang-17 cmake curl extra-cmake-modules git libasound2-dev libcurl4-openssl-dev libdbus-1-dev libdecor-0-dev libegl-dev libevdev-dev \
+  libfontconfig-dev libfreetype-dev libfuse2 libgtk-3-dev libgudev-1.0-dev libharfbuzz-dev libinput-dev libopengl-dev libpipewire-0.3-dev libpulse-dev \
+  libssl-dev libudev-dev libva-dev libwayland-dev libx11-dev libx11-xcb-dev libxcb1-dev libxcb-composite0-dev libxcb-cursor-dev libxcb-damage0-dev \
+  libxcb-glx0-dev libxcb-icccm4-dev libxcb-image0-dev libxcb-keysyms1-dev libxcb-present-dev libxcb-randr0-dev libxcb-render0-dev libxcb-render-util0-dev \
+  libxcb-shape0-dev libxcb-shm0-dev libxcb-sync-dev libxcb-util-dev libxcb-xfixes0-dev libxcb-xinput-dev libxcb-xkb-dev libxext-dev libxkbcommon-x11-dev \
+  libxrandr-dev lld-17 llvm-17 nasm ninja-build patchelf pkg-config zlib1g-dev

scripts/retry.sh

@@ -1,13 +0,0 @@
-#!/bin/bash
-
-RETRIES=10
-
-for i in $(seq 1 "$RETRIES"); do
-	"$@" && break
-	if [ "$i" == "$RETRIES" ]; then
-		echo "Command \"$@\" failed after ${RETRIES} retries."
-		exit 1
-	fi
-done
-
-exit 0