valgrind suppressions: ignore XInitThreads leaks

As we load that symbol dynamically, valgrind gets confused
when it leaks and reports the leak against an unrelated library
and an unknown (??) symbol.

To address that, put the loading and calling of that symbol
in a separate function, and ignore any malloc leak happening
in that function.

tests/check/generic/states.c

@@ -203,12 +203,14 @@ GST_START_TEST (test_state_changes_down_seq)
 
 GST_END_TEST;
 
-
-static Suite *
-states_suite (void)
+/* Separate function because XInitThreads leaks, but valgrind
+ * gets confused when a dynamically loaded symbol leaks, and
+ * shows it as a ??? symbol in an unrelated library, making
+ * it awkward to ignore in the suppression files
+ */
+static void
+call_xinitthreads (void)
 {
-  Suite *s = suite_create ("states_base");
-  TCase *tc_chain = tcase_create ("general");
   GModule *libx11;
 
   libx11 =
@@ -220,6 +222,15 @@ states_suite (void)
     }
     g_module_close (libx11);
   }
+}
+
+static Suite *
+states_suite (void)
+{
+  Suite *s = suite_create ("states_base");
+  TCase *tc_chain = tcase_create ("general");
+
+  call_xinitthreads ();
 
   suite_add_tcase (s, tc_chain);
   tcase_add_checked_fixture (tc_chain, setup, teardown);

tests/check/gst-plugins-base.supp

@@ -569,3 +569,12 @@
    fun:glXChooseFBConfig
    fun:gst_gl_context_glx_choose_format
 }
+{
+   <a one time alloc>
+   Memcheck:Leak
+   match-leak-kinds: definite
+   fun:malloc
+   ...
+   fun:call_xinitthreads
+   fun:states_suite
+}