Fix withTemporaryDirectory compilation on Windows

Author: kateinoigakukun

Tests/WITExtractorTests/TestSupport.swift

@@ -47,9 +47,18 @@ struct TestSupport {
         let templatePath = tempdir.appendingPathComponent("WasmKit.XXXXXX")
         var template = [UInt8](templatePath.path.utf8).map({ Int8($0) }) + [Int8(0)]
 
+        #if os(Windows)
+        if _mktemp_s(&template, template.count) != 0 {
+            throw Error(errno: errno)
+        }
+        if _mkdir(template) != 0 {
+            throw Error(errno: errno)
+        }
+        #else
         if mkdtemp(&template) == nil {
             throw Error(errno: errno)
         }
+        #endif
 
         let path = String(cString: template)
         defer { _ = try? FileManager.default.removeItem(atPath: path) }