literal matching: separate path for pure literal patterns

src/scratch.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2018, Intel Corporation
+ * Copyright (c) 2015-2019, Intel Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -208,6 +208,7 @@ struct ALIGN_CL_DIRECTIVE hs_scratch {
     u64a *fdr_conf; /**< FDR confirm value */
     u8 fdr_conf_offset; /**< offset where FDR/Teddy front end matches
                          * in buffer */
+    u8 pure; /**< indicator of pure-literal or cutting-literal */
 };
 
 /* array of fatbit ptr; TODO: why not an array of fatbits? */