It is unreliable to target i386

LLVM may emit `bswap` instructions in the binary even with the `-march i386` option, making it unreliable to use `i386-unknown-none-gnu` as an intermediate step. https://github.com/llvm/llvm-project/issues/58470

Start by reproducing the i386 build described in the issue and inspect the generated binary for bswap instructions. Read the linked LLVM issue to understand the compiler behavior and possible constraints. Done would require establishing a reliable intermediate-target approach or clearly documenting that this target cannot provide that guarantee.

Written by the indexing model from the issue text.