Add missing ATTR_UNUSED (PR bootstrap/90808).

2019-06-10  Martin Liska  <mliska@suse.cz>

	PR bootstrap/90808
	* libgcov.h: Add ATTRIBUTE_UNUSED.

From-SVN: r272114

libgcc/ChangeLog

 2019-06-10  Martin Liska  <mliska@suse.cz>
 
+	PR bootstrap/90808
+	* libgcov.h: Add ATTRIBUTE_UNUSED.
+
+2019-06-10  Martin Liska  <mliska@suse.cz>
+
 	* Makefile.in: Add __gcov_one_value_profiler_v2,
 	__gcov_one_value_profiler_v2_atomic and
 	__gcov_indirect_call_profiler_v4.

libgcc/libgcov.h

@@ -328,7 +328,7 @@ gcov_get_counter (void)
    when read value is equal to IGNORE_SCALING.  */
 
 static inline gcov_type
-gcov_get_counter_ignore_scaling (gcov_type ignore_scaling)
+gcov_get_counter_ignore_scaling (gcov_type ignore_scaling ATTRIBUTE_UNUSED)
 {
 #ifndef IN_GCOV_TOOL
   /* This version is for reading count values in libgcov runtime: