Refactor the compilers out of libart.

This builds three separate compilers and dynamically links with the right one
at runtime.

Change-Id: I59d22b9884f41de733c09f97e29ee290236d5f4b
diff --git a/src/dalvik_system_VMStack.cc b/src/dalvik_system_VMStack.cc
index 7425847..37ee8b2 100644
--- a/src/dalvik_system_VMStack.cc
+++ b/src/dalvik_system_VMStack.cc
@@ -17,6 +17,7 @@
 #include "jni_internal.h"
 #include "class_loader.h"
 #include "object.h"
+#include "scoped_heap_lock.h"
 #include "thread_list.h"
 
 #include "JniConstants.h" // Last to avoid problems with LOG redefinition.