Update ICU to 58.1

source/i18n/datefmt.cpp

Index: source/i18n/datefmt.cpp
diff --git a/source/i18n/datefmt.cpp b/source/i18n/datefmt.cpp
index 4f7a1046ea01c2a58833039ba80775d593cdc45a..2767e3f382917d1f7cff546674b4bfa1ac921d57 100644
--- a/source/i18n/datefmt.cpp
+++ b/source/i18n/datefmt.cpp
@@ -1,3 +1,5 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
 /*
  *******************************************************************************
  * Copyright (C) 1997-2015, International Business Machines Corporation and    *
@@ -317,7 +319,7 @@ DateFormat::format(UDate date, UnicodeString& appendTo) const
 {
     // Note that any error information is just lost.  That's okay
     // for this convenience method.
-    FieldPosition fpos(0);
+    FieldPosition fpos(FieldPosition::DONT_CARE);
     return format(date, appendTo, fpos);
 }