NSAttributedString: define writing direction constants

Define constants for defining an attributed string's writing direction.

Headers/AppKit/NSAttributedString.h

@@ -196,6 +196,14 @@ enum
 };
 #endif
 
+#if OS_API_VERSION(MAC_OS_X_VERSION_10_11, GS_API_LATEST)
+typedef NSInteger NSWritingDirectionFormatType;
+enum {
+  NSWritingDirectionEmbedding = (0 << 1),
+  NSWritingDirectionOverride = (1 << 1)
+};
+#endif
+
 @interface NSAttributedString (AppKit)
 - (BOOL) containsAttachments;
 - (NSDictionary*) fontAttributesInRange: (NSRange)range;

Headers/AppKit/NSParagraphStyle.h

@@ -58,6 +58,9 @@ enum _NSWritingDirection {
     NSWritingDirectionLeftToRight,
     NSWritingDirectionRightToLeft
 };
+enum {
+  NSWritingDirectionNatural = NSWritingDirectionNaturalDirection
+};
 typedef NSInteger NSWritingDirection;
 
 #if OS_API_VERSION(MAC_OS_X_VERSION_10_3, GS_API_LATEST)

Headers/AppKit/NSText.h

@@ -77,6 +77,11 @@ typedef enum _NSTextAlignment {
   NSNaturalTextAlignment
 } NSTextAlignment;
 
+enum {
+  NSTextWritingDirectionEmbedding = (0 << 1),
+  NSTextWritingDirectionOverride = (1 << 1)
+};
+
 enum {
   NSIllegalTextMovement	= 0,
   NSReturnTextMovement	= 0x10,