patch 8.2.0846: build failure with small features

Problem:    Build failure with small features.
Solution:   Add #ifdef.

src/undo.c

@@ -375,6 +375,7 @@ u_save_line(undoline_T *ul, linenr_T lnum)
     return ul->ul_line == NULL ? FAIL : OK;
 }
 
+#ifdef FEAT_PROP_POPUP
 /*
  * return TRUE if line "lnum" has text property "flags".
  */
@@ -395,6 +396,7 @@ has_prop_w_flags(linenr_T lnum, int flags)
     }
     return FALSE;
 }
+#endif
 
 /*
  * Common code for various ways to save text before a change.

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    846,
 /**/
     845,
 /**/