perf ui gtk: Add perf_gtk__show_helpline() for pr_*

Use helpline for printing error/debug messages. The code resembles a TUI
counter part and only print the first line of the message.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1345104894-14205-5-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/ui/helpline.h b/tools/perf/ui/helpline.h
index 61118b2..a2487f9 100644
--- a/tools/perf/ui/helpline.h
+++ b/tools/perf/ui/helpline.h
@@ -4,6 +4,8 @@
 #include <stdio.h>
 #include <stdarg.h>
 
+#include "../util/cache.h"
+
 struct ui_helpline {
 	void (*pop)(void);
 	void (*push)(const char *msg);
@@ -21,4 +23,25 @@
 
 extern char ui_helpline__current[512];
 
+#ifdef NO_NEWT_SUPPORT
+static inline int ui_helpline__show_help(const char *format __used,
+					 va_list ap __used)
+{
+	return 0;
+}
+#else
+extern char ui_helpline__last_msg[];
+int ui_helpline__show_help(const char *format, va_list ap);
+#endif /* NO_NEWT_SUPPORT */
+
+#ifdef NO_GTK2_SUPPORT
+static inline int perf_gtk__show_helpline(const char *format __used,
+					  va_list ap __used)
+{
+	return 0;
+}
+#else
+int perf_gtk__show_helpline(const char *format, va_list ap);
+#endif /* NO_GTK2_SUPPORT */
+
 #endif /* _PERF_UI_HELPLINE_H_ */