Features: Add cxx_inline_namespaces.
Features: Expect cxx_variadic_templates to implement N2555.

N2555 is essentially a bugfix and predates most compiler releases which
aimed to experimentally support variadic templates.
Features: Add cxx_thread_local.
Features: Add cxx_sizeof_member.
Features: Add cxx_decltype_incomplete_return_types.
Features: Add cxx_right_angle_brackets.
Use a cxx_attributes test that does not produce a warning.
Fix extern templates version.
Allow variadic macros only in C++11 mode for now.
Features: Add cxx_default_function_template_args.
Features: Add cxx_enum_forward_declarations.
Features: Add cxx_extended_friend_declarations.
Features: Add cxx_local_type_template_args.
Features: Add cxx_func_identifier.
Fix reference for cxx_decltype.
Features: Add cxx_long_long_type.
Add reference comment.
Add note about rvalue references.
Revert "Refactor the test a bit. Build only one target."

This reverts commit 3784e268feb65e7bf85a0fc259da6c91a17ea182.
Merge topic 'cxx11-features' into next

bafca7a2 Revert "Refactor the test a bit. Build only one target."
d10b31d4 Add note about rvalue references.
bb1db2d0 Add reference comment.
1f22be4e Features: Add cxx_long_long_type.
5da18c3b Fix reference for cxx_decltype.
2a55d7f0 Features: Add cxx_func_identifier.
880f5d8f Features: Add cxx_local_type_template_args.
d70fbbe5 Features: Add cxx_extended_friend_declarations.
449a8f55 Features: Add cxx_enum_forward_declarations.
b9dec3c1 Features: Add cxx_default_function_template_args.
2734a843 Allow variadic macros only in C++11 mode for now.
92d1a1d3 Fix extern templates version.
fe1a8151 Use a cxx_attributes test that does not produce a warning.
ea9de1af Features: Add cxx_right_angle_brackets.
c526bdea Features: Add cxx_decltype_incomplete_return_types.
dd92a2a5 Features: Add cxx_sizeof_member.
...