Split <test/build_info.h> out of test_common.h

The header `test_common.h` contains two kinds of things:

* Things to do at the beginning of individual C files. Specifically,
  defining macros that notify system headers about what we want from them.
  Keep those in `test_common.h`, which will subsequently be moved out of
  the include directory.
* Things to do at the beginning of every header. In particular, read the
  library configuration. Move them to a new header `build_info.h`,
  which is the only one intended to be included from headers.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

Author: gilles-peskine-arm

tests/include/test/build_info.h

@@ -0,0 +1,24 @@
+/**
+ * \file test/build_info.h
+ *
+ * \brief Common things for all Mbed TLS and TF-PSA-Crypto test headers.
+ *
+ * Include this header first in all headers in `include/test/`.
+ */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef TEST_BUILD_INFO_H
+#define TEST_BUILD_INFO_H
+
+#include <mbedtls/build_info.h>
+
+/* Most fields of publicly available structs are private and are wrapped with
+ * MBEDTLS_PRIVATE macro. This define allows tests to access the private fields
+ * directly (without using the MBEDTLS_PRIVATE wrapper). */
+#define MBEDTLS_ALLOW_PRIVATE_ACCESS
+
+#endif /* TEST_BUILD_INFO_H */

tests/include/test/test_common.h

@@ -3,8 +3,7 @@
  *
  * \brief Common things for all Mbed TLS and TF-PSA-Crypto test code.
  *
- * Include this header first in all headers in `include/test/`.
- * Include this or another header from `include/test/` in all test C files.
+ * Include this header first in all test C files.
  */
 
 /*
@@ -24,11 +23,8 @@
 #define __USE_MINGW_ANSI_STDIO 1
 #endif
 
-#include <mbedtls/build_info.h>
-
-/* Most fields of publicly available structs are private and are wrapped with
- * MBEDTLS_PRIVATE macro. This define allows tests to access the private fields
- * directly (without using the MBEDTLS_PRIVATE wrapper). */
-#define MBEDTLS_ALLOW_PRIVATE_ACCESS
+/* Make sure we have the library configuration, and anything else that
+ * is deemed necessary in test headers. */
+#include <test/build_info.h>
 
 #endif /* TEST_TEST_COMMON_H */