Adding some clarifications to func_speex doxygen docs.

The functions needed doesn't exist in Speex 1.05 which is what a lot of distros use.
1.2 seems to have been in beta status for years, and does include the sexy functions needed for func_speex to work.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@227237 65c4cc65-6c06-0410-ace0-fbb531ad65f3

funcs/func_speex.c

@@ -26,7 +26,8 @@
  *
  * \ingroup functions
  *
- * \extref The Speex library - http://www.speex.org
+ * \extref The Speex 1.2 library - http://www.speex.org
+ * \note Requires the 1.2 version of the Speex library (which might not be what you find in Linux packages)
  */
 
 /*** MODULEINFO