patch 8.0.0425: build errors when building without folding

Problem:    Build errors when building without folding.
Solution:   Add #ifdefs. (John Marriott)
diff --git a/src/edit.c b/src/edit.c
index 25896f3..6621515 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -541,8 +541,8 @@
 
     /*
      * Handle restarting Insert mode.
-     * Don't do this for "CTRL-O ." (repeat an insert): we get here with
-     * restart_edit non-zero, and something in the stuff buffer.
+     * Don't do this for "CTRL-O ." (repeat an insert): In that case we get
+     * here with something in the stuff buffer.
      */
     if (restart_edit != 0 && stuff_empty())
     {
@@ -1453,10 +1453,14 @@
 
 docomplete:
 	    compl_busy = TRUE;
+#ifdef FEAT_FOLDING
 	    disable_fold_update++;  /* don't redraw folds here */
+#endif
 	    if (ins_complete(c, TRUE) == FAIL)
 		compl_cont_status = 0;
+#ifdef FEAT_FOLDING
 	    disable_fold_update--;
+#endif
 	    compl_busy = FALSE;
 	    break;
 #endif /* FEAT_INS_EXPAND */