Replace #pragma once with #ifndef #define #endif logic because #pragma once does not work cleanly on OSX

include/cpu_aes.h

@@ -3,7 +3,8 @@
  * License.....: MIT
  */
 
-#pragma once
+#ifndef _CPU_AES_H
+#define _CPU_AES_H
 
 /* AES context.  */
 typedef struct aes_context
@@ -24,3 +25,5 @@ void AES_encrypt (AES_KEY *aes_key, const u8 *input, u8 *output);
 void AES_decrypt (AES_KEY *aes_key, const u8 *input, u8 *output);
 
 void AES128_decrypt_cbc (const u32 key[4], const u32 iv[4], const u32 in[16], u32 out[16]);
+
+#endif // _CPU_AES_H