patch 8.1.2373: cannot build with +popupwin but without +quickfix

Problem:    Cannot build with +popupwin but without +quickfix. (John Marriott)
Solution:   Adjust #ifdefs.
diff --git a/src/popupwin.c b/src/popupwin.c
index 5385296..dc09ef3 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -2386,8 +2386,10 @@
     if (wp != NULL)
     {
 	popup_show(wp);
+#ifdef FEAT_QUICKFIX
 	if (wp->w_popup_flags & POPF_INFO)
 	    pum_position_info_popup(wp);
+#endif
     }
 }
 
@@ -3686,6 +3688,13 @@
     return abort;
 }
 
+    int
+popup_is_popup(win_T *wp)
+{
+    return wp->w_popup_flags != 0;
+}
+
+#if defined(FEAT_QUICKFIX) || defined(PROTO)
 /*
  * Find an existing popup used as the preview window, in the current tab page.
  * Return NULL if not found.
@@ -3702,13 +3711,6 @@
     return NULL;
 }
 
-    int
-popup_is_popup(win_T *wp)
-{
-    return wp->w_popup_flags != 0;
-}
-
-#if defined(FEAT_QUICKFIX) || defined(PROTO)
 /*
  * Find an existing popup used as the info window, in the current tab page.
  * Return NULL if not found.
@@ -3729,19 +3731,28 @@
     void
 f_popup_findinfo(typval_T *argvars UNUSED, typval_T *rettv)
 {
+#ifdef FEAT_QUICKFIX
     win_T   *wp = popup_find_info_window();
 
     rettv->vval.v_number = wp == NULL ? 0 : wp->w_id;
+#else
+    rettv->vval.v_number = 0;
+#endif
 }
 
     void
 f_popup_findpreview(typval_T *argvars UNUSED, typval_T *rettv)
 {
+#ifdef FEAT_QUICKFIX
     win_T   *wp = popup_find_preview_window();
 
     rettv->vval.v_number = wp == NULL ? 0 : wp->w_id;
+#else
+    rettv->vval.v_number = 0;
+#endif
 }
 
+#if defined(FEAT_QUICKFIX) || defined(PROTO)
 /*
  * Create a popup to be used as the preview or info window.
  * NOTE: this makes the popup the current window, so that the file can be
@@ -3775,7 +3786,6 @@
     return OK;
 }
 
-#if defined(FEAT_QUICKFIX) || defined(PROTO)
 /*
  * Close any preview popup.
  */
@@ -3851,6 +3861,7 @@
     }
 }
 
+# if defined(FEAT_QUICKFIX) || defined(PROTO)
 /*
  * If there is a preview window, update the title.
  * Used after changing directory.
@@ -3863,5 +3874,6 @@
     if (wp != NULL)
 	popup_set_title(wp);
 }
+# endif
 
 #endif // FEAT_PROP_POPUP