Add missing include files for simd.

simd.c

@@ -16,6 +16,9 @@
  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include "library.h"
 #include "simd.h"
 
@@ -209,4 +212,4 @@ int have_arm_crypto(void)
     return getauxval(AT_HWCAP2) & HWCAP2_AES;
 #endif
 }
-#endif
+#endif