Compiling Rust with GCC: an update

So it appears them are compiling the SIMD themselves, and bypassing LLVM and GCC's SIMD support, both of which were pretty good except for that no languages could really use them (I gave a talk about this at the 2019 LLVM conference, and wrote a patch series for Zig that only about half of it ever got merged, but I would still recommend Zig over C for this, as C's extensions have some problems that cannot be fixed except by starting over from C11.)

> many developers are concerned by the fact that there is only one compiler available;

I don't think 10 independent C++ compilers would be enough to convince Linus to allow C++ in Linux.