validator_ragel: Link into TCB, use under env var

src/trusted/service_runtime/sel_main_chrome.c

Index: src/trusted/service_runtime/sel_main_chrome.c
diff --git a/src/trusted/service_runtime/sel_main_chrome.c b/src/trusted/service_runtime/sel_main_chrome.c
index 1ed3492c9a0501e726fde03300eade814e289336..f60b6ad82b3c7d34871454d51cbdc6a08ffa35cc 100644
--- a/src/trusted/service_runtime/sel_main_chrome.c
+++ b/src/trusted/service_runtime/sel_main_chrome.c
@@ -49,6 +49,7 @@ struct NaClChromeMainArgs *NaClChromeMainArgsCreate(void) {
   args->broker_duplicate_handle_func = NULL;
   args->attach_debug_exception_handler_func = NULL;
 #endif
+  args->enable_dfa_validator = 0;
   return args;
 }
 
@@ -130,6 +131,11 @@ void NaClChromeMainStart(struct NaClChromeMainArgs *args) {
     NaClSetBrokerDuplicateHandleFunc(args->broker_duplicate_handle_func);
 #endif
 
+  if (args->enable_dfa_validator) {
+    fprintf(stderr, "DANGER! USING THE UNSTABLE DFA VALIDATOR!\n");
+    nap->enable_dfa_validator = 1;
+  }
+
   NaClAppInitialDescriptorHookup(nap);
 
   /*