Add GSK_LINE_JOIN_ARCS

Implementation will follow.

gsk/gskenums.h

@@ -225,6 +225,7 @@ typedef enum {
  *   the joint point
  * @GSK_LINE_JOIN_BEVEL: use a cut-off join, the join is cut off at half
  *   the line width from the joint point
+ * @GSK_LINE_JOIN_ARCS: Use a sharp angled corner made from circles
  *
  * Specifies how to render the junction of two lines when stroking.
  *
@@ -237,7 +238,8 @@ typedef enum {
   GSK_LINE_JOIN_MITER,
   GSK_LINE_JOIN_MITER_CLIP,
   GSK_LINE_JOIN_ROUND,
-  GSK_LINE_JOIN_BEVEL
+  GSK_LINE_JOIN_BEVEL,
+  GSK_LINE_JOIN_ARCS
 } GskLineJoin;
 
 /**

gsk/gskpathstroke.c

@@ -469,6 +469,7 @@ add_line_join (GskPathBuilder         *builder,
 
   switch (line_join)
     {
+    case GSK_LINE_JOIN_ARCS:
     case GSK_LINE_JOIN_MITER:
     case GSK_LINE_JOIN_MITER_CLIP:
       {

gsk/gskstroke.c

@@ -124,6 +124,7 @@ gsk_stroke_to_cairo (const GskStroke *self,
     {
       case GSK_LINE_JOIN_MITER:
       case GSK_LINE_JOIN_MITER_CLIP:
+      case GSK_LINE_JOIN_ARCS:
         cairo_set_line_join (cr, CAIRO_LINE_JOIN_MITER);
         break;
       case GSK_LINE_JOIN_ROUND: