[Bug preprocessor/61613] ,##__VA_ARGS__ fails to expand the first variadic argument if it is a macro-name

[arthur.j.odwyer at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61613

--- Comment #7 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
@David, sadly, I'm not set up to build or test GCC patches, nor am I registered
as a contributor. Anyone else want to step up?

I could suggest test cases, perhaps, but I wouldn't be good at shepherding this
patch all the way through the process-I've-never-done-before.