Don't apply the same patch multiple times

Author: kateinoigakukun

Diff for: lib/ruby_wasm/cli.rb

@@ -266,7 +266,7 @@ def self.build_source_aliases(root)
         source[:patches] = patches_dirs.flat_map do |patches_dir|
           Dir[File.join(patches_dir, name, "*.patch")]
             .map { |p| File.expand_path(p) }
-        end
+        end.uniq
       end
 
       build_manifest = File.join(root, "build_manifest.json")