Temporarily include private symbols in sample programs

Signed-off-by: Ben Taylor <ben.taylor@linaro.org>
diff --git a/programs/ssl/ssl_test_lib.h b/programs/ssl/ssl_test_lib.h
index 1dda8d6..5cfa7d2 100644
--- a/programs/ssl/ssl_test_lib.h
+++ b/programs/ssl/ssl_test_lib.h
@@ -7,6 +7,9 @@
 
 #ifndef MBEDTLS_PROGRAMS_SSL_SSL_TEST_LIB_H
 #define MBEDTLS_PROGRAMS_SSL_SSL_TEST_LIB_H
+#define MBEDTLS_DECLARE_PRIVATE_IDENTIFIERS
+
+#include "mbedtls/private/pk_private.h"
 
 #include "mbedtls/build_info.h"