Fix ret code in udp_proxy.c
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index 5797f3d..cacd4f3 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -37,10 +37,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
-#define mbedtls_time       time
-#define mbedtls_time_t     time_t
-#define mbedtls_printf     printf
-#endif
+#define mbedtls_time            time
+#define mbedtls_time_t          time_t
+#define mbedtls_printf          printf
+#define MBEDTLS_EXTI_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
 
 #if !defined(MBEDTLS_NET_C)
 int main( void )
@@ -600,7 +602,8 @@
 
 int main( int argc, char *argv[] )
 {
-    int ret;
+    int ret = 1;
+    int exit_code = MBEDTLS_EXIT_FAILURE;
 
     mbedtls_net_context listen_fd, client_fd, server_fd;
 
@@ -781,10 +784,12 @@
 
     }
 
+    exit_code = MBEDTLS_EXIT_SUCCESS;
+
 exit:
 
 #ifdef MBEDTLS_ERROR_C
-    if( ret != 0 )
+    if( exit_code != MBEDTLS_EXIT_SUCCESS )
     {
         char error_buf[100];
         mbedtls_strerror( ret, error_buf, 100 );
@@ -802,7 +807,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret != 0 );
+    return( exit_code );
 }
 
 #endif /* MBEDTLS_NET_C */