[Bug c++/70922] -Wparentheses warning should not complain about if-else from macro expansion

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70922

--- Comment #3 from Pedro Alves <palves at redhat dot com> ---
> I noticed that this triggers with C++, but not with C.  (GDB recently switched > to building as C++ program by default.)

I've built trunk now (gcc version 7.0.0 20160503), and I now get the same
warning on both C and C++.