Merge pull request #4669 from willmmiles/4597-usermods-not-building

Correct issues with usermods not being linked.
- Explicitly set libArchive: false in usermod library.json files
- Fix up symlink path generation on Windows
- Add validation script to report usermod linkage in resulting binary

usermods/BH1750_v2/library.json

@@ -1,5 +1,6 @@
 {
   "name": "BH1750_v2",
+  "build": { "libArchive": false },
   "dependencies": {
     "claws/BH1750":"^1.2.0"
   }