Workaround for Range#relative_to

This is a workaround until https://bugs.ruby-lang.org/issues/6203
is addressed and we can apply the fix from there. Or this will be
a permanent work around in the unlikely case that the change is
rejected.

range.c

@@ -969,6 +969,8 @@ range_relative_to(VALUE range, SEL sel, VALUE max)
 {
     long beg, len, m = NUM2LONG(max);
     rb_range_beg_len(range, &beg, &len, m, 0);
+    if (beg + len - 1 > m)
+      len -= 1;
     return rb_range_new(LONG2NUM(beg), LONG2NUM(beg + len - 1), 0);
 }
 

spec/macruby/core/range_spec.rb

@@ -11,9 +11,8 @@
   it "responds to #relative_to, which returns a new Range object without negative indicies" do
     ( 0 ..  10).relative_to(11).should == (0..10)
     ( 1 ..  9 ).relative_to(11).should == (1..9 )
-    ##
-    # TODO: This spec fails right now, though it is the intended behaviour.
-    # ( 0 ..  15).relative_to(11).should == (0..10)
+    ( 0 ..  15).relative_to(11).should == (0..10)
+    ( 0 ..  11).relative_to(11).should == (0..10)
 
     ( 0 .. -1 ).relative_to(11).should == (0..10)
     ( 0 .. -2 ).relative_to(11).should == (0..9 )
@@ -24,6 +23,7 @@
     (-10.. -5 ).relative_to(11).should == (1..6 )
 
     ( 4 ... 11).relative_to(11).should == (4..10)
+    ( 4 ... 15).relative_to(11).should == (4..10)
     ( 4 ... 10).relative_to(11).should == (4..9 )
     ( 4 ...-1 ).relative_to(11).should == (4..9 )
     (-11...-1 ).relative_to(11).should == (0..9 )