perf_counter tools: add in basic glue from Git

First very raw version at having a central 'perf' command and
a list of subcommands:

  perf top
  perf stat
  perf record
  perf report
  ...

This is done by picking up Git's collection of utility functions,
and hacking them to build fine in this new environment.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/Documentation/perf_counter/builtin.h b/Documentation/perf_counter/builtin.h
new file mode 100644
index 0000000..4163744
--- /dev/null
+++ b/Documentation/perf_counter/builtin.h
@@ -0,0 +1,18 @@
+#ifndef BUILTIN_H
+#define BUILTIN_H
+
+#include "util.h"
+#include "strbuf.h"
+
+extern const char perf_version_string[];
+extern const char perf_usage_string[];
+extern const char perf_more_info_string[];
+
+extern void list_common_cmds_help(void);
+extern const char *help_unknown_cmd(const char *cmd);
+extern void prune_packed_objects(int);
+extern int read_line_with_nul(char *buf, int size, FILE *file);
+extern int check_pager_config(const char *cmd);
+
+extern int cmd_top(int argc, const char **argv, const char *prefix);
+#endif