Document check-config.h and *adjust*.h as internal headers

Including *adjust*.h directly is likely to cause them to be applied at the
wrong time, resulting in an invalid or unintended configuration.

Including check_config.h at the wrong time is likely to cause spurious
errors.

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

include/mbedtls/check_config.h

@@ -2,6 +2,13 @@
  * \file check_config.h
  *
  * \brief Consistency checks for configuration options
+ *
+ * This is an internal header. Do not include it directly.
+ *
+ * This header is included automatically by all public Mbed TLS headers
+ * (via mbedtls/build_info.h). Do not include it directly in a configuration
+ * file such as mbedtls/mbedtls_config.h or #MBEDTLS_USER_CONFIG_FILE!
+ * It would run at the wrong time due to missing derived symbols.
  */
 /*
  *  Copyright The Mbed TLS Contributors

include/mbedtls/config_adjust_legacy_crypto.h

@@ -2,6 +2,8 @@
  * \file mbedtls/config_adjust_legacy_crypto.h
  * \brief Adjust legacy configuration configuration
  *
+ * This is an internal header. Do not include it directly.
+ *
  * Automatically enable certain dependencies. Generally, MBEDLTS_xxx
  * configurations need to be explicitly enabled by the user: enabling
  * MBEDTLS_xxx_A but not MBEDTLS_xxx_B when A requires B results in a

include/mbedtls/config_adjust_legacy_from_psa.h

@@ -2,6 +2,8 @@
  * \file mbedtls/config_adjust_legacy_from_psa.h
  * \brief Adjust PSA configuration: activate legacy implementations
  *
+ * This is an internal header. Do not include it directly.
+ *
  * When MBEDTLS_PSA_CRYPTO_CONFIG is enabled, activate legacy implementations
  * of cryptographic mechanisms as needed to fulfill the needs of the PSA
  * configuration. Generally speaking, we activate a legacy mechanism if

include/mbedtls/config_adjust_psa_from_legacy.h

@@ -2,6 +2,8 @@
  * \file mbedtls/config_adjust_psa_from_legacy.h
  * \brief Adjust PSA configuration: construct PSA configuration from legacy
  *
+ * This is an internal header. Do not include it directly.
+ *
  * When MBEDTLS_PSA_CRYPTO_CONFIG is disabled, we automatically enable
  * cryptographic mechanisms through the PSA interface when the corresponding
  * legacy mechanism is enabled. In many cases, this just enables the PSA

include/mbedtls/config_adjust_psa_superset_legacy.h

@@ -2,6 +2,8 @@
  * \file mbedtls/config_adjust_psa_superset_legacy.h
  * \brief Adjust PSA configuration: automatic enablement from legacy
  *
+ * This is an internal header. Do not include it directly.
+ *
  * To simplify some edge cases, we automatically enable certain cryptographic
  * mechanisms in the PSA API if they are enabled in the legacy API. The general
  * idea is that if legacy module M uses mechanism A internally, and A has

include/mbedtls/config_adjust_ssl.h

@@ -2,6 +2,8 @@
  * \file mbedtls/config_adjust_ssl.h
  * \brief Adjust TLS configuration
  *
+ * This is an internal header. Do not include it directly.
+ *
  * Automatically enable certain dependencies. Generally, MBEDLTS_xxx
  * configurations need to be explicitly enabled by the user: enabling
  * MBEDTLS_xxx_A but not MBEDTLS_xxx_B when A requires B results in a

include/mbedtls/config_adjust_x509.h

@@ -2,6 +2,8 @@
  * \file mbedtls/config_adjust_x509.h
  * \brief Adjust X.509 configuration
  *
+ * This is an internal header. Do not include it directly.
+ *
  * Automatically enable certain dependencies. Generally, MBEDLTS_xxx
  * configurations need to be explicitly enabled by the user: enabling
  * MBEDTLS_xxx_A but not MBEDTLS_xxx_B when A requires B results in a

include/psa/crypto_adjust_auto_enabled.h

@@ -2,6 +2,8 @@
  * \file psa/crypto_adjust_auto_enabled.h
  * \brief Adjust PSA configuration: enable always-on features
  *
+ * This is an internal header. Do not include it directly.
+ *
  * Always enable certain features which require a negligible amount of code
  * to implement, to avoid some edge cases in the configuration combinatorics.
  */

include/psa/crypto_adjust_config_key_pair_types.h

@@ -2,6 +2,8 @@
  * \file psa/crypto_adjust_config_key_pair_types.h
  * \brief Adjust PSA configuration for key pair types.
  *
+ * This is an internal header. Do not include it directly.
+ *
  * See docs/proposed/psa-conditional-inclusion-c.md.
  * - Support non-basic operations in a keypair type implicitly enables basic
  *   support for that keypair type.

include/psa/crypto_adjust_config_synonyms.h

@@ -2,6 +2,8 @@
  * \file psa/crypto_adjust_config_synonyms.h
  * \brief Adjust PSA configuration: enable quasi-synonyms
  *
+ * This is an internal header. Do not include it directly.
+ *
  * When two features require almost the same code, we automatically enable
  * both when either one is requested, to reduce the combinatorics of
  * possible configurations.