patch 8.1.1535: popup select test fails on Mac

Problem:    Popup select test fails on Mac.
Solution:   Skip test if clipboard feature not available.

src/testdir/test_popupwin.vim

@@ -323,6 +323,9 @@ func Test_popup_select()
   if !CanRunVimInTerminal()
     throw 'Skipped: cannot make screendumps'
   endif
+  if !has('clipboard')
+    throw 'Skipped: clipboard feature missing'
+  endif
   " create a popup with some text to be selected
   let lines =<< trim END
     call setline(1, range(1, 20))

src/version.c

@@ -777,6 +777,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1535,
 /**/
     1534,
 /**/