> Certainly not the Linux kernel itself, that relies too heavily on GCC quirks. True, but there was a large effort to clone in LLVM nearly all the GCC extensio

> Certainly not the Linux kernel itself, that relies too heavily on GCC quirks. True, but there was a large effort to clone in LLVM nearly all the GCC extensions and quirks that the Linux kernel requires, so that nowadays the Linux kernel can be mostly compiled also with LLVM. See https://bugs.llvm.org/show_bug.cgi?id=4068 https://bugs.llvm.org/show_bug.cgi?id=4068 and its long list of dependencies to get an idea of what had to be done.