Write notes to stderr

Author: grynspan

Sources/Testing/ExitTests/SpawnProcess.swift

@@ -57,13 +57,13 @@ private let _posix_spawn_file_actions_addclosefrom_np = symbol(named: "posix_spa
 /// consistently available across all platforms that implement the
 /// `posix_spawn()` API.
 private let _posix_spawn_file_actions_addchdir = symbol(named: "posix_spawn_file_actions_addchdir").map {
-  print("!!FOUND posix_spawn_file_actions_addchdir")
+  try! FileHandle.stderr.write("!!FOUND posix_spawn_file_actions_addchdir\n")
   return castCFunction(at: $0, to: (@convention(c) (UnsafeMutablePointer<P<posix_spawn_file_actions_t>>, UnsafePointer<CChar>) -> CInt).self)
 } ?? symbol(named: "posix_spawn_file_actions_addchdir_np").map {
-  print("!!FOUND posix_spawn_file_actions_addchdir_np")
+  try! FileHandle.stderr.write("!!FOUND posix_spawn_file_actions_addchdir_np\n")
   return castCFunction(at: $0, to: (@convention(c) (UnsafeMutablePointer<P<posix_spawn_file_actions_t>>, UnsafePointer<CChar>) -> CInt).self)
 } ?? {
-  print("!!DID NOT FIND posix_spawn_file_actions_addchdir[_np]")
+  try! FileHandle.stderr.write("!!DID NOT FIND posix_spawn_file_actions_addchdir[_np]\n")
   return nil
 }()
 #endif
@@ -163,11 +163,13 @@ func spawnExecutable(
           // posix_spawn(), so set it here in the parent process and hope
           // another thread does not stomp on the change (as Foundation does.)
           // Platforms known to take this path: Amazon Linux 2, OpenBSD, QNX
-          print("!!CALLING chdir")
+          try! FileHandle.stderr.write("!!CALLING chdir\n")
           guard 0 == chdir(currentDirectoryPath) else {
             throw CError(rawValue: swt_errno())
           }
         }
+
+        throw SystemError(description: "Early exiting to report on chdir.")
       }
 
       // Forward standard I/O streams and any explicitly added file handles.