Add simple debug hit rate counter

Add a very simple debug framework to
measure the hit rate of a given condition.

Simply insert macro

dbg_hit_on(x);

Anywhere you want to compute hit rate of condition x
and then call, as example in poll(), function
dbg_print_hit_rate() to print current results.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/misc.cpp

@@ -38,15 +38,31 @@ int gettimeofday(struct timeval * tp, struct timezone * tzp);
 
 #include <cstdio>
 #include <iomanip>
+#include <iostream>
 #include <sstream>
 
 #include "misc.h"
 
 
+////
+//// Variables
+////
+
+long dbg_cnt0 = 0;
+long dbg_cnt1 = 0;
+
+
 //// 
 //// Functions
 ////
 
+void dbg_print_hit_rate() {
+    
+  std::cout << "Total " << dbg_cnt0 << " Hit " << dbg_cnt1
+            << " hit rate (%) " << (dbg_cnt1*100)/(dbg_cnt0 ? dbg_cnt0 : 1)
+            << std::endl;
+}
+
 /// engine_name() returns the full name of the current Glaurung version.
 /// This will be either "Glaurung YYMMDD" (where YYMMDD is the date when the
 /// program was compiled) or "Glaurung <version number>", depending on whether