[PATCH v2 0/2] changes for addding fchmodat2 syscall

[Rich Felker]

I'm resubmitting this split into two parts, first blocking chmod of
symlinks in chmod_common, then adding the new syscall, as requested by
Christoph. This will make it impossible to chmod symlinks via the
O_PATH magic symlink path. I've also reordered the unsupported flags
test to come first.

Rich