chore: Update alpha-build.sh script to handle xvfb-run not found and enable lazy loading for images

.github/workflows/alpha.yml

@@ -273,7 +273,17 @@ jobs:
           sudo rm -rf "/usr/local/share/boost"
           sudo rm -rf "$AGENT_TOOLSDIRECTORY"
 
+      - name: "win-cross Cache"
+        env:
+          SEGMENT_DOWNLOAD_TIMEOUT_MINS: 5
+        id: cache-win-cross
+        uses: actions/cache@v4
+        with:
+          path: ${HOME}/win-cross
+          key: clang-17
+
       - name: Setup For Windows
+        if: steps.cache-win-cross.outputs.cache-hit != 'true'
         run: |
           set -x
           mkdir -p ~/win-cross
@@ -288,7 +298,8 @@ jobs:
           sudo apt install -y msitools python3-pip
           ./mach python --virtualenv build taskcluster/scripts/misc/get_vs.py build/vs/vs2022.yaml ~/win-cross/vs2022
           
- 
+      - name: Bootstrap
+        run: |
           cat ../.github/workflows/src/windows_mozconfig >> ../configs/common/mozconfig
 
           cd ..

.github/workflows/src/windows_mozconfig

@@ -24,13 +24,14 @@ export WINE="$TOOLS/wine/bin/wine64"
 #export WIN32_REDIST_DIR="$TOOLS"/vs2022/VC/Redist/MSVC/14.34.31931/x64/Microsoft.VC143.CRT
 #export WIN_UCRT_REDIST_DIR="$TOOLS/vs2022/Windows Kits/10/Redist/10.0.22621.0/ucrt/DLLs/x64"
 
-export RUSTFLAGS="$RUSTFLAGS -Ctarget-cpu=x86-64"
+export RUSTFLAGS="$RUSTFLAGS -Ctarget-cpu=x86-64-v3"
 
 ac_add_options --enable-default-browser-agent
 ac_add_options --enable-install-strip
 ac_add_options --enable-jxl
 ac_add_options --disable-maintenance-service
 ac_add_options --disable-profiling
+ac_add_options --disable-accessibility
 
 ac_add_options --disable-bits-download
 

configs/common/mozconfig

@@ -63,8 +63,6 @@ if test "$ZEN_RELEASE"; then
   ac_add_options MOZ_LTO=full
   ac_add_options --enable-lto=full
 
-  ac_add_options --without-wasm-sandboxed-libraries
-
   mk_add_options MOZILLA_OFFICIAL=1
 
   MOZILLA_OFFICIAL=1

configs/linux/mozconfig

@@ -3,7 +3,7 @@ ac_add_options --enable-wasm-avx
 # not when cross compiling
 if ! test "$ZEN_CROSS_COMPILING"; then
     if test "$ZEN_RELEASE"; then
-        export RUSTFLAGS="$RUSTFLAGS -Ctarget-cpu=x86-64"
+        export RUSTFLAGS="$RUSTFLAGS -Ctarget-cpu=x86-64-v3"
     fi
 
     if test -d "$HOME/.mozbuild/clang/bin"; then