Add simple profiling class to accumulate Stmt usage stats across runs.

Use the BROFILER_FILE environment variable to point to a file in
which Stmt usage statistics from Bro script-layer can be output.

This should be able to be used to check Bro script coverage that
that e.g. the entire test suite covers.

src/main.cc

@@ -47,9 +47,12 @@ extern "C" void OPENSSL_add_all_algorithms_conf(void);
 #include "ConnCompressor.h"
 #include "DPM.h"
 #include "BroDoc.h"
+#include "Brofiler.h"
 
 #include "binpac_bro.h"
 
+Brofiler brofiler;
+
 #ifndef HAVE_STRSEP
 extern "C" {
 char* strsep(char**, const char*);
@@ -260,6 +263,8 @@ void terminate_bro()
 
 	terminating = true;
 
+	brofiler.WriteStats();
+
 	EventHandlerPtr bro_done = internal_handler("bro_done");
 	if ( bro_done )
 		mgr.QueueEvent(bro_done, new val_list);
@@ -335,6 +340,7 @@ static void bro_new_handler()
 
 int main(int argc, char** argv)
 	{
+	brofiler.ReadStats();
 	bro_argc = argc;
 	bro_argv = new char* [argc];