Update ICU to 58.1

source/i18n/rbt_rule.cpp

Index: source/i18n/rbt_rule.cpp
diff --git a/source/i18n/rbt_rule.cpp b/source/i18n/rbt_rule.cpp
index b21e37c9cea951ce98592da3dbe102c53889a148..36a07d9a9759f882ff112d556b86fba46c6f846a 100644
--- a/source/i18n/rbt_rule.cpp
+++ b/source/i18n/rbt_rule.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) 1999-2011, International Business Machines
@@ -174,7 +176,7 @@ TransliterationRule::TransliterationRule(TransliterationRule& other) :
     segmentsCount = 0;
     if (other.segmentsCount > 0) {
         segments = (UnicodeFunctor **)uprv_malloc(other.segmentsCount * sizeof(UnicodeFunctor *));
-        uprv_memcpy(segments, other.segments, other.segmentsCount*sizeof(segments[0]));
+        uprv_memcpy(segments, other.segments, (size_t)other.segmentsCount*sizeof(segments[0]));
     }
 
     if (other.anteContext != NULL) {