Rename identifiers containing double-underscore
Rename identifiers containing double-underscore (`__`) to avoid `__`.
The reason to avoid double-underscore is that all identifiers
containing double-underscore are reserved in C++. Rename all such
identifiers that appear in any public header, including ssl_internal.h
which is in principle private but in practice is installed with the
public headers.
This commit makes check-names.sh pass.
```
perl -i -pe 's/\bMBEDTLS_SSL__ECP_RESTARTABLE\b/MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED/g; s/\bMBEDTLS_KEY_EXCHANGE_(_\w+)_(_\w+)\b/MBEDTLS_KEY_EXCHANGE${1}${2}/g' include/mbedtls/*.h library/*.c programs/*/*.c scripts/data_files/rename-1.3-2.0.txt tests/suites/*.function
```
diff --git a/programs/ssl/mini_client.c b/programs/ssl/mini_client.c
index 4b8140e..b4346bb 100644
--- a/programs/ssl/mini_client.c
+++ b/programs/ssl/mini_client.c
@@ -88,7 +88,7 @@
const char *pers = "mini_client";
-#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
const unsigned char psk[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
@@ -211,7 +211,7 @@
mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
-#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
mbedtls_ssl_conf_psk( &conf, psk, sizeof( psk ),
(const unsigned char *) psk_id, sizeof( psk_id ) - 1 );
#endif