diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index dcfc0fc..7354082 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -32,6 +32,7 @@
 #include <stdlib.h>
 #define mbedtls_snprintf        snprintf
 #define mbedtls_printf          printf
+#define mbedtls_exit            exit
 #define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
 #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
 #endif /* MBEDTLS_PLATFORM_C */
@@ -59,10 +60,14 @@
 #include <stdio.h>
 #include <string.h>
 
-#if defined( MBEDTLS_CHECK_PARAMS ) && defined(MBEDTLS_PLATFORM_C)
-void mbedtls_param_failed( char* failure_condition, char* file, int line )
+#if defined(MBEDTLS_CHECK_PARAMS)
+#include "mbedtls/platform_util.h"
+void mbedtls_param_failed( const char *failure_condition,
+                           const char *file,
+                           int line )
 {
-    mbedtls_printf("%s:%i: Input param failed - %sn", file, line,                           failure_condition );
+    mbedtls_printf( "%s:%i: Input param failed - %s\n",
+                    file, line, failure_condition );
     mbedtls_exit( MBEDTLS_EXIT_FAILURE );
 }
 #endif