Make ICU build with Clang. ...

third_party/icu/public/common/unicode/unistr.h

 /*
 **********************************************************************
 *   Copyright (C) 1998-2010, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 **********************************************************************
 *
 * File unistr.h
 *
 * Modification History:
 *
@@ skipping 4071 matching lines @@
 UnicodeString::extract(int32_t start,
                int32_t _length,
                char *dst,
                const char *codepage) const
 
 {
   // This dstSize value will be checked explicitly
 #if defined(__GNUC__)
   // Ticket #7039: Clip length to the maximum valid length to the end of addressable memory given the starting address
   // This is only an issue when using GCC and certain optimizations are turned on.
-  return extract(start, _length, dst, dst!=0 ? ((dst >= (char*)((size_t)-1) - UINT32_MAX) ? (((char*)UINT32_MAX) - dst) : UINT32_MAX) : 0, codepage);
+  return extract(start, _length, dst, dst!=0 ? ((dst >= (char*)((size_t)-1) - UINT32_MAX) ? static_cast<unsigned int>((((char*)UINT32_MAX) - dst)) : UINT32_MAX) : 0, codepage);
 #else
   return extract(start, _length, dst, dst!=0 ? 0xffffffff : 0, codepage);
 #endif
 }
 
 #endif
 
 inline void
 UnicodeString::extractBetween(int32_t start,
                   int32_t limit,
@@ skipping 334 matching lines @@
 { return doReverse(0, length()); }
 
 inline UnicodeString&
 UnicodeString::reverse(int32_t start,
                int32_t _length)
 { return doReverse(start, _length); }
 
 U_NAMESPACE_END
 
 #endif