diff --git a/programs/hash/generic_sum.c b/programs/hash/generic_sum.c
index 20ff252..9183874 100644
--- a/programs/hash/generic_sum.c
+++ b/programs/hash/generic_sum.c
@@ -29,22 +29,25 @@
 #if defined(POLARSSL_PLATFORM_C)
 #include "polarssl/platform.h"
 #else
-#define polarssl_printf     printf
+#include <stdio.h>
 #define polarssl_fprintf    fprintf
+#define polarssl_printf     printf
 #endif
 
-#include <string.h>
-#include <stdio.h>
-
+#if defined(POLARSSL_MD_C) && defined(POLARSSL_FS_IO)
 #include "polarssl/md.h"
 
-#if !defined(POLARSSL_MD_C)
+#include <stdio.h>
+#include <string.h>
+#endif
+
+#if !defined(POLARSSL_MD_C) || !defined(POLARSSL_FS_IO)
 int main( int argc, char *argv[] )
 {
     ((void) argc);
     ((void) argv);
 
-    polarssl_printf("POLARSSL_MD_C not defined.\n");
+    polarssl_printf("POLARSSL_MD_C and/or POLARSSL_FS_IO not defined.\n");
     return( 0 );
 }
 #else
@@ -225,4 +228,4 @@
 
     return( ret );
 }
-#endif /* POLARSSL_MD_C */
+#endif /* POLARSSL_MD_C && POLARSSL_FS_IO */