Define MBEDTLS_DECLARE_PRIVATE_IDENTIFIERS in every sample program

Add #define MBEDTLS_DECLARE_PRIVATE_IDENTIFIERS to every sample program
before the first include so that mbedtls doesn't break with future
privatization work.

Signed-off-by: Felix Conway <felix.conway@arm.com>
diff --git a/programs/aes/crypt_and_hash.c b/programs/aes/crypt_and_hash.c
index b2cd704..e3bfb3c 100644
--- a/programs/aes/crypt_and_hash.c
+++ b/programs/aes/crypt_and_hash.c
@@ -10,6 +10,7 @@
  * set before mbedtls_config.h, which pulls in glibc's features.h indirectly.
  * Harmless on other platforms. */
 #define _POSIX_C_SOURCE 200112L
+#define MBEDTLS_DECLARE_PRIVATE_IDENTIFIERS
 
 #include "mbedtls/build_info.h"