avoid passing a char[] as snprintf first argument. implemented

* encoding.c parserInternals.c: avoid passing a char[] as snprintf
  first argument.
* threads.c include/libxml/threads.h: implemented xmlIsThreadsEnabled()
  based on Andrew W. Nosenko idea.
* doc/* elfgcchack.h: regenerated the API
Daniel

threads.c

@@ -164,6 +164,24 @@ static xmlRMutexPtr	xmlLibraryLock = NULL;
 static void xmlOnceInit(void);
 #endif
 
+/**
+ * xmlIsThreadsEnabled:
+ *
+ * Run-time information about whether multithread support is compiled in
+ *
+ * Returns 1 (true) if library was compiled with multithread support
+ * enabled or 0 (false) otherwise.
+ */
+int
+xmlIsThreadsEnabled(void)
+{
+#ifdef LIBXML_THREAD_ENABLED
+    return 1;
+#else
+    return 0;
+#endif
+}
+
 /**
  * xmlNewMutex:
  *