[pjmlp]

Many of those C compilers are stuck in old versions like C89, and full of vendor extensions only relevant to a special CPU of an embedded vendor, compiling code that can hardly be acknowledged as ISO C.

Many of those vendors are slowly throwing away these proprietary toolchains, some of them are actually GCC forks, never ever updated, and replacing them with clang.

So it depends, on how much those vendors will care to support Rust for their customers, or if those kind of customers even care about anything else than their beloved C dialect.