ECDH: Fix inclusion of platform.h for proper use of MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED
diff --git a/programs/test/benchmark.c b/programs/test/benchmark.c
index ada42df..fc84f57 100644
--- a/programs/test/benchmark.c
+++ b/programs/test/benchmark.c
@@ -25,9 +25,8 @@
 #include MBEDTLS_CONFIG_FILE
 #endif
 
-#if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
-#else
+#if !defined(MBEDTLS_PLATFORM_C)
 #include <stdio.h>
 #include <stdlib.h>
 #define mbedtls_exit       exit