Add missing platform macro defines in pk_decrypt.c
diff --git a/programs/pkey/pk_decrypt.c b/programs/pkey/pk_decrypt.c
index b60f6ca..00bd71e 100644
--- a/programs/pkey/pk_decrypt.c
+++ b/programs/pkey/pk_decrypt.c
@@ -29,8 +29,11 @@
#include "mbedtls/platform.h"
#else
#include <stdio.h>
-#define mbedtls_printf printf
-#endif
+#include <stdlib.h>
+#define mbedtls_printf printf
+#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
#if defined(MBEDTLS_BIGNUM_C) && defined(MBEDTLS_PK_PARSE_C) && \
defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_C) && \