Can you confirm whether or not anonymous member structures originated with the Plan 9 C compiler? I know I first learned of them from the Plan 9 compiler documentation, but that was long after they were already in GCC. I can't find when they were added to Microsoft's C compiler, but I'm guessing GCC's "-fms-extensions" flag is so named simply because it originated as a compatibility option for the MinGW project, and doesn't by itself imply they were a Microsoft invention. GCC gained -fms-extensions and anonymous member structures in 1999, and MinGW is first mentioned in GCC in 1997. (Which maybe suggests Microsoft C gained anonymous structure members between 1997 and 1999?)
Relatedly, do you know if anonymous member unions originate with C++, Plan 9 C, or elsewhere?
For this use case, at least, it feels like a CS version of racism. MSFT is bad, so no MSFT.
It largely clears up an idiosyncrasy from the evolution of C.
(but, as someone that briefly worked on plan9 in 1995/96, I like your idea :)