patch 9.1.1248: compile error when building without FEAT_QUICKFIX

Problem:  compile error when building without FEAT_QUICKFIX
Solution: adjust ifdefs in popupwin.c, add CheckFeature quickfix
          to a few tests (John Marriott, Hirohito Higashi)

closes: #16940
closes: #16962

Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>
Co-authored-by: Zoltan Arpadffy <zoltan.arpadffy@gmail.com>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_vim9_cmd.vim b/src/testdir/test_vim9_cmd.vim
index 26a3f09..d76e3bd 100644
--- a/src/testdir/test_vim9_cmd.vim
+++ b/src/testdir/test_vim9_cmd.vim
@@ -2108,12 +2108,14 @@
 
 " Test for the 'previewpopup' option
 def Test_previewpopup()
+  CheckFeature quickfix
   set previewpopup=height:10,width:60
   pedit Xppfile
   s:check_previewpopup('Xppfile')
 enddef
 
 def Test_previewpopup_pbuffer()
+  CheckFeature quickfix
   set previewpopup=height:10,width:60
   edit Xppfile
   pbuffer