don't install sysroots on windows (#29)

not necessary, and windows tar hangs when extracting the sysroots.

Author: ardera

.github/workflows/build.yml

@@ -180,8 +180,8 @@ jobs:
         run: |
           gclient sync --no-history --shallow --revision .@${{ needs.resolve-version.outputs.engine-ref || needs.resolve-version.outputs.engine-hash }} -R -D
 
-      - name: Install linux arm sysroot
-        if: steps.cache-lookup.outputs.cache-hit != 'true'
+      - name: Install linux sysroots (macOS/Linux)
+        if: steps.cache-lookup.outputs.cache-hit != 'true' && runner.os != 'Windows'
         working-directory: flutter/engine/src/build/linux/sysroot_scripts
         run: |
           ./install-sysroot.py --arch=arm

dot-gclient.py

@@ -4,7 +4,7 @@
   "url": "https://github.com/flutter/flutter.git",
   "deps_file": "DEPS",
   "custom_vars": {
-    "download_linux_deps": True,
+    "download_linux_deps": False,
     "download_android_deps": False,
     "download_esbuild": False,
     "download_fuchsia_deps": False,