Fix Looper.Executor macOS build

Author: colemancda

Sources/AndroidLooper/SerialExecutor.swift

@@ -73,23 +73,25 @@ public extension Looper {
 internal extension Looper.Executor {
 
     func configureLooper() throws(AndroidLooperError) {
+        #if os(Android)
         do {
             // add to looper
             try looper.handle.add(fileDescriptor: .init(rawValue: eventFd.rawValue), callback: drainAExecutor, data: Unmanaged.passUnretained(self).toOpaque()).get()
         }
         catch {
-            #if os(Android)
             try? eventFd.close()
-            #endif
             throw error
         }
+        #endif
     }
 
     /// Read number of remaining events from eventFd
     var eventsRemaining: UInt64 {
         get throws {
             #if os(Android)
             try eventFd.read().rawValue
+            #else
+            0
             #endif
         }
     }