Merge mbedtls 2.16.6 into baremetal

Conflicts:
mbedtls.doxyfile - PROJECT_NAME - mbed TLS v2.16.6 chosen.
doc_mainpage.h - mbed TLS v2.16.6 version chosen.
hmac_drbg.h - line 260, extended description chosen.
            - line 313, extended description chosen.
            - line 338, extended description chosen.
version.h - 2.16.6 chosen.
CMakeLists.txt - 2.16.6 chosen.
test_suite_version.data - 2.16.6 chosen.
Makefile - 141 - manual correction - baremetal version of C_SOURCE_FILES
                 with variables for directories plus 2.16.6 CTAGS addition.
pkparse.c - lines 846 onwards - the asn1_get_nonzero_mpi implementation chosen.
ssl_tls.c - line 5269 - edited manually, left the ret=0, because baremetal has
            a different behaviour since commit 87b5626, but added a debug
            message that's new in 2.16.6.    
all.sh:
- component_build_deprecated - chosen the refactored version from 2.16.6,
                               but with extra flags from baremetal.
- rest of the _no_xxx tests - merged make options to have PTHREAD=1 and
                              other changes from 2.16.6 (like -O1 instead of -O0).
- component_build_arm_none_eabi_gcc_no_64bit_multiplication - added 
                              TINYCRYPT_BUILD=0 to the 2.16.6 version of make.

x509/req_app.c - left baremetal log but with mbedtls_exit( 0 ) call.
x509/crl_app.c - left baremetal log but with mbedtls_exit( 0 ) call.
x509/cert_app.c - left baremetal log but with mbedtls_exit( 0 ) call.
ssl/ssl_mail_client.c - left baremetal log but with mbedtls_exit( 0 ) call.
ssl/ssl_pthread_server.c - left baremetal log but with mbedtls_exit( 0 ) call.
ssl/ssl_fork_server.c - left baremetal log but with mbedtls_exit( 0 ) call.
ssl_client1.c - line 54 - left baremetal log but with mbedtls_exit( 0 ) call.
ssl_client2.c - line 54 - left baremetal log but with mbedtls_exit( 0 ) call.
              - line 132 - new options of both branches added.
              - skip close notify handled as in 2.16.6, but with `ssl` instead of `&ssl`.
              - Merged the 2.16.6 usage split with additional baremetal usages.
              - Merged options from baremetal and 2.16.6.
ssl_server.c - left baremetal log but with mbedtls_exit( 0 ) call.
ssl_server2.c - Merged the 2.16.6 usage split with additional baremetal usages.
config.pl - fixed missing defines from the documentation, removed duplicates,
            and reorganised so that the documentation and excluded list
            are ordered in the same way.
test_suite_x509parse.data - only added the two new pathlen tests.
x509_crt.c - change the return code by removing
             MBEDTLS_ERR_X509_INVALID_EXTENSIONS, since it's added by
             x509_crt_frame_parse_ext not by an "or", but by "+=".
Changelog - Assigned all entries to appropriate sections.
ssl-opt.sh - line 8263 - merged options.
           - removed lines 1165 - 1176 - there was a duplicate test, probably
             an artifact of previous merges.
check-files.py - sticked to old formatting.

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/tests/suites/helpers.function b/tests/suites/helpers.function
index 4b53da7..84b4dcd 100644
--- a/tests/suites/helpers.function
+++ b/tests/suites/helpers.function
@@ -235,6 +235,40 @@
     mbedtls_exit( 1 );                                             \
 }
 
+#if defined(__GNUC__)
+/* Test if arg and &(arg)[0] have the same type. This is true if arg is
+ * an array but not if it's a pointer. */
+#define IS_ARRAY_NOT_POINTER( arg )                                     \
+    ( ! __builtin_types_compatible_p( __typeof__( arg ),                \
+                                      __typeof__( &( arg )[0] ) ) )
+#else
+/* On platforms where we don't know how to implement this check,
+ * omit it. Oh well, a non-portable check is better than nothing. */
+#define IS_ARRAY_NOT_POINTER( arg ) 1
+#endif
+
+/* A compile-time constant with the value 0. If `const_expr` is not a
+ * compile-time constant with a nonzero value, cause a compile-time error. */
+#define STATIC_ASSERT_EXPR( const_expr )                                \
+    ( 0 && sizeof( struct { int STATIC_ASSERT : 1 - 2 * ! ( const_expr ); } ) )
+/* Return the scalar value `value` (possibly promoted). This is a compile-time
+ * constant if `value` is. `condition` must be a compile-time constant.
+ * If `condition` is false, arrange to cause a compile-time error. */
+#define STATIC_ASSERT_THEN_RETURN( condition, value )   \
+    ( STATIC_ASSERT_EXPR( condition ) ? 0 : ( value ) )
+
+#define ARRAY_LENGTH_UNSAFE( array )            \
+    ( sizeof( array ) / sizeof( *( array ) ) )
+/** Return the number of elements of a static or stack array.
+ *
+ * \param array         A value of array (not pointer) type.
+ *
+ * \return The number of elements of the array.
+ */
+#define ARRAY_LENGTH( array )                                           \
+    ( STATIC_ASSERT_THEN_RETURN( IS_ARRAY_NOT_POINTER( array ),         \
+                                 ARRAY_LENGTH_UNSAFE( array ) ) )
+
 /*
  * 32-bit integer manipulation macros (big endian)
  */