Merge pull request #2793 from apple/icu-before-62

Work around ICU version < 62

Author: DougGregor

CoreFoundation/String.subproj/CFString.c

@@ -28,6 +28,7 @@
 #include "CFRuntime_Internal.h"
 #include <assert.h>
 #include <unicode/uchar.h>
+#include <unicode/uversion.h>
 #if TARGET_OS_MAC || TARGET_OS_WIN32 || TARGET_OS_LINUX
 #include "CFLocaleInternal.h"
 #include "CFStringLocalizedFormattingInternal.h"
@@ -46,7 +47,10 @@
 #endif
 
 
-
+// Build with older versions of ICU
+#if U_ICU_VERSION_MAJOR_NUM < 62
+#  define UCHAR_EXTENDED_PICTOGRAPHIC 64
+#endif
 
 #define USE_STRING_ROM 0