Add back U_WCHAR_IS_UTF32 macro to pmac.h...

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

 /*
 ******************************************************************************
 *
 *   Copyright (C) 1997-2010, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************
 *
 * Note: autoconf creates platform.h from platform.h.in at configure time.
 *
@@ skipping 390 matching lines @@
 
 #if U_HAVE_LIB_SUFFIX
 # ifndef U_ICU_ENTRY_POINT_RENAME
 /* Renaming pattern:    u_strcpy_41_suffix */
 #  define U_ICU_ENTRY_POINT_RENAME(x)    x ## _ ## 46 ## 
 #  define U_DEF_ICUDATA_ENTRY_POINT(major, minor) icudt####major##minor##_dat
 
 # endif
 #endif
 
+/*===========================================================================*/
+/* Local defines                                                             */
+/*===========================================================================*/
+
+/* On the Mac, we define U_WCHAR_IS_UTF32 to treat wchar_t as though it
+   contains UTF-32 at all times.  Strictly speaking, that's not entirely
+   correct given Mac's libc (__STDC_ISO_10646__ is not defined) , but provided
+   that we ignore libc's locale support (by not calling setlocale) and its
+   multibyte string support, this should be fine.  Our codebase makes enough
+   other assumptions about a UTF-8 locale and UTF-32 wchar_t strings for this
+   to make sense. */
+#define U_WCHAR_IS_UTF32
+
 #endif