Regression from Changeset 80234: preprocessor undefined behaviour in type_traits

[Hubert Tong <hstong@…>]

process_jam_log refuses to build for the AIX runner. The build appears to be choking on undefined behaviour introduced in the subject changeset.

   306      BOOST_STATIC_CONSTANT(bool, value =
   307  #ifndef BOOST_NO_RVALUE_REFERENCES
   308          sizeof( _m_check(static_cast<rvalue_type>(_m_from)) ) == sizeof(::boost::type_traits::yes_type)
   309  #else
   310          sizeof( _m_check(_m_from) ) == sizeof(::boost::type_traits::yes_type)
   311  #endif
   312          );

N3290 subclause 16.3 [cpp.replace] paragraph 11 (re: invocations of a function-like macro):

...

If there are sequences of preprocessing tokens within the list of arguments that would otherwise act as preprocessing directives, the behaviour is undefined.

[Michel Morin]

Thanks for the report, Hubert!

John, sorry for the bad patch. Since fixing this is trivial, I'll commit a fix.

[Michel Morin]

(In [80325]) Fix preprocessor usage (and synchronize the style); fixes #7306