mbedTLS: THREADING_SUPPORT compilation fix

Closes #505

lib/vtls/mbedtls.c

@@ -173,15 +173,17 @@ mbedtls_connect_step1(struct connectdata *conn,
 
 #ifdef THREADING_SUPPORT
   entropy_init_mutex(&entropy);
+  mbedtls_ctr_drbg_init(&connssl->ctr_drbg);
 
-  if((ret = mbedtls_ctr_drbg_init(&connssl->ctr_drbg, entropy_func_mutex,
-                                  &entropy, connssl->ssn.id,
-                                  connssl->ssn.length)) != 0) {
+  ret = mbedtls_ctr_drbg_seed(&connssl->ctr_drbg, entropy_func_mutex,
+                              &entropy, connssl->ssn.id,
+                              connssl->ssn.id_len);
+  if(ret) {
 #ifdef MBEDTLS_ERROR_C
-     mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
+    mbedtls_strerror(ret, errorbuf, sizeof(errorbuf));
 #endif /* MBEDTLS_ERROR_C */
-     failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
-                                                            -ret, errorbuf);
+    failf(data, "Failed - mbedTLS: ctr_drbg_init returned (-0x%04X) %s\n",
+          -ret, errorbuf);
   }
 #else
   mbedtls_entropy_init(&connssl->entropy);

lib/vtls/polarssl_threadlock.c

@@ -22,7 +22,7 @@
  ***************************************************************************/
 #include "curl_setup.h"
 
-#if defined(USE_POLARSSL) && \
+#if (defined(USE_POLARSSL) || defined(USE_MBEDTLS)) && \
     (defined(USE_THREADS_POSIX) || defined(USE_THREADS_WIN32))
 
 #if defined(USE_THREADS_POSIX)
@@ -150,4 +150,4 @@ int polarsslthreadlock_unlock_function(int n)
   return 1; /* OK */
 }
 
-#endif /* USE_POLARSSL */
+#endif /* USE_POLARSSL || USE_MBEDTLS */