gcov: add support for GCC 4.9

This patch handles the gcov-related changes in GCC 4.9:

  A new counter (time profile) is added. The total number is 9 now.

  A new profile merge function __gcov_merge_time_profile is added.

See gcc/gcov-io.h and libgcc/libgcov-merge.c

For the first change, the layout of struct gcov_info is affected.

For the second one, a dummy function is added to kernel/gcov/base.c
similarly.

Signed-off-by: Yuan Pengfei <coolypf@qq.com>
Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c
index f45b75b..b358a80 100644
--- a/kernel/gcov/base.c
+++ b/kernel/gcov/base.c
@@ -85,6 +85,12 @@
 }
 EXPORT_SYMBOL(__gcov_merge_ior);
 
+void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_time_profile);
+
 /**
  * gcov_enable_events - enable event reporting through gcov_event()
  *