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/wince_main.c b/programs/wince_main.c
index e817b9f..de11162 100644
--- a/programs/wince_main.c
+++ b/programs/wince_main.c
@@ -7,6 +7,8 @@
 
 #if defined(_WIN32_WCE)
 
+#define MBEDTLS_DECLARE_PRIVATE_IDENTIFIERS
+
 #include <windows.h>
 
 extern int main(int, const char **);