Add baremetal configuration to `configs` folder
This commit adds a minimal test configuration `baremetal.h` to the `configs`
folder supporting ECDHE-ECDSA-AES-CCM-8 with Secp256R1 and SHA-256 only.
The configuration lacks some options which are currently needed to
successfully build and run the example applications `ssl_client2`
and `ssl_server2`, such as `MBEDTLS_NET_C`. To still allow testing
a configuration close to `baremetal.h`, the commit also adds
`baremetal_test.h`, containing minimal amendments to `baremetal.h`
that allow building and running `ssl_client2` and `ssl_server2`.
diff --git a/configs/baremetal_test.h b/configs/baremetal_test.h
new file mode 100644
index 0000000..4b51212
--- /dev/null
+++ b/configs/baremetal_test.h
@@ -0,0 +1,57 @@
+/**
+ * \file baremetal_test.h
+ *
+ * \brief This file contains minimal modifications to the
+ * baremetal configuration `baremetal.h` which allows
+ * example programs to compile and run.
+ *
+ * It should be used as the `MBEDTLS_USER_CONFIG_FILE`
+ * in builds using `baremetal.h`.
+ */
+/*
+ * Copyright (C) 2006-2018, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#ifndef MBEDTLS_BAREMETAL_USER_CONFIG_H
+#define MBEDTLS_BAREMETAL_USER_CONFIG_H
+
+/* We need test CRTs to be able to run ssl_client2 and ssl_server2. */
+#define MBEDTLS_CERTS_C
+/* For the network context used by ssl_client2 and ssl_server2. */
+#define MBEDTLS_NET_C
+/* Debug output */
+#define MBEDTLS_DEBUG_C
+
+/* We don't have DER-encoded test CRTs yet. */
+#define MBEDTLS_PEM_PARSE_C
+#define MBEDTLS_BASE64_C
+/* We don't have Secp256r1 test CRTs at the moment. */
+#define MBEDTLS_ECP_DP_SECP384R1_ENABLED
+
+/* ssl_client2 and ssl_server2 use CTR-DRBG so far. */
+#define MBEDTLS_CTR_DRBG_C
+
+/* The ticket implementation hardcodes AES-GCM */
+#define MBEDTLS_GCM_C
+
+/* Use Mbed TLS' timer implementation for Linux. */
+#define MBEDTLS_TIMING_C
+
+#undef MBEDTLS_NO_PLATFORM_ENTROPY
+
+#endif /* MBEDTLS_BAREMETAL_USER_CONFIG_H */