perf_counter tools: Introduce stricter C code checking

Tighten up our C code requirements:

 - disallow warnings
 - disallow declarations-mixed-with-statements
 - require proper prototypes
 - require C99 (with gcc extensions)

Fix up a ton of problems these measures unearth:

 - unused functions
 - needlessly global functions
 - missing prototypes
 - code mixed with declarations

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20090526222155.GJ4424@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/Documentation/perf_counter/builtin-stat.c b/Documentation/perf_counter/builtin-stat.c
index e7cb941..ce661e2 100644
--- a/Documentation/perf_counter/builtin-stat.c
+++ b/Documentation/perf_counter/builtin-stat.c
@@ -30,6 +30,7 @@
  */
 
 #include "perf.h"
+#include "builtin.h"
 #include "util/util.h"
 #include "util/parse-options.h"
 #include "util/parse-events.h"
@@ -108,7 +109,7 @@
 	}
 }
 
-int do_perfstat(int argc, const char **argv)
+static int do_perfstat(int argc, const char **argv)
 {
 	unsigned long long t0, t1;
 	int counter;