Fix platform-specific missing bits

Author: grynspan

Sources/Testing/ExitTests/ExitTest.swift

@@ -679,7 +679,7 @@ extension ExitTest {
     Environment.setVariable(nil, named: name)
 
     var fd: CInt?
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android)
     fd = CInt(environmentVariable)
 #elseif os(Windows)
     if let handle = UInt(environmentVariable).flatMap(HANDLE.init(bitPattern:)) {

Sources/Testing/ExitTests/SpawnProcess.swift

@@ -88,7 +88,7 @@ func spawnExecutable(
   }
 #endif
 
-#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD)
+#if SWT_TARGET_OS_APPLE || os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android)
   return try withUnsafeTemporaryAllocation(of: P<posix_spawn_file_actions_t>.self, capacity: 1) { fileActions in
     let fileActionsInitialized = posix_spawn_file_actions_init(fileActions.baseAddress!)
     let fileActions = asArgument(fileActions)