Lua Add Emergency Garbage Collector

Derivative of work by RobertGabrielJakabosky
 http://lua-users.org/wiki/EmergencyGarbageCollector

I've only implemented the not enough memory part and
 expanded this idea to adding a mechanism to signal
 the OOM condition of the plugin buffer which allows us to only
 grab the playback buffer after garbage collection fails
 (SO THE MUSIC KEEPS PLAYING AS LONG AS POSSIBLE)

Change-Id: I684fb98b540ffc01f7ba324ab5b761ceb59b9f9b

apps/plugins/lua/lstate.h

@@ -71,6 +71,7 @@ typedef struct global_State {
   void *ud;         /* auxiliary data to `frealloc' */
   lu_byte currentwhite;
   lu_byte gcstate;  /* state of garbage collector */
+  lu_byte gcflags;  /* flags for the garbage collector */
   int sweepstrgc;  /* position of sweep in `strt' */
   GCObject *rootgc;  /* list of all collectable objects */
   GCObject **sweepgc;  /* position of sweep in `rootgc' */