Replace use of deprecated C Standard library headers in C++ code.

Change-Id: I9fa6630c7e4bdb2897df34d417635d8c7d8253bc
Signed-off-by: Tyler Chatow <tchatow@gmail.com>
diff --git a/frc971/input/drivetrain_input.h b/frc971/input/drivetrain_input.h
index 9e450d5..3419ea7 100644
--- a/frc971/input/drivetrain_input.h
+++ b/frc971/input/drivetrain_input.h
@@ -1,11 +1,9 @@
 #ifndef AOS_INPUT_DRIVETRAIN_INPUT_H_
 #define AOS_INPUT_DRIVETRAIN_INPUT_H_
 
-#include <math.h>
-#include <stdio.h>
-#include <string.h>
-
 #include <cmath>
+#include <cstdio>
+#include <cstring>
 #include <memory>
 
 #include "aos/logging/logging.h"