diff --git a/test/testsupport/perf_test.h b/test/testsupport/perf_test.h
index fbc1ef9..4f718bb 100644
--- a/test/testsupport/perf_test.h
+++ b/test/testsupport/perf_test.h
@@ -71,7 +71,7 @@
 
 // By default, perf results are printed to stdout. Set the FILE* to where they
 // should be printing instead.
-void SetPerfResultsOutput(const FILE* output);
+void SetPerfResultsOutput(FILE* output);
 
 // You shouldn't use this function. It's only used to test the functions above.
 void ClearPerfResults();