[PATCH 2/7] winegstreamer: Make append_element accpet NULL arguments.

[Ziqing Hui]

From: Ziqing Hui

---
 dlls/winegstreamer/unixlib.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/dlls/winegstreamer/unixlib.c b/dlls/winegstreamer/unixlib.c
index 4fcf7d0d469..f2e0b1ca2fe 100644
--- a/dlls/winegstreamer/unixlib.c
+++ b/dlls/winegstreamer/unixlib.c
@@ -145,16 +145,17 @@ bool append_element(GstElement *container, GstElement *element, GstElement **fir

if (!gst_bin_add(GST_BIN(container), element) ||
             !gst_element_sync_state_with_parent(element) ||
-            (*last && !gst_element_link(*last, element)))
+            (last && *last && !gst_element_link(*last, element)))
     {
         GST_ERROR("Failed to link %s element.", name);
     }
     else
     {
         GST_DEBUG("Linked %s element %p.", name, element);
-        if (!*first)
+        if (first && !*first)
             *first = element;
-        *last = element;
+        if (last)
+            *last = element;
         success = true;
     }