Add support for DEBUG context type.

Bug: 7343201

This change adds switching for the debug runtime (libclcore_debug.bc) when
running under a DEBUG RS context. It also fixes a small naming issue for
rsSetElementAt_int().

Change-Id: I8b574c9ce915a440375530325ba7de2b46707cfd
diff --git a/rsDefines.h b/rsDefines.h
index 242d649..6e080de 100644
--- a/rsDefines.h
+++ b/rsDefines.h
@@ -300,6 +300,9 @@
     RS_ERROR_OUT_OF_MEMORY = 4,
     RS_ERROR_DRIVER = 5,
 
+    // Errors that only occur in the debug context.
+    RS_ERROR_FATAL_DEBUG = 0x0800,
+
     RS_ERROR_FATAL_UNKNOWN = 0x1000,
     RS_ERROR_FATAL_DRIVER = 0x1001,
     RS_ERROR_FATAL_PROGRAM_LINK = 0x1002