vfs:  Axe std::transform() use in dynamic_group.cc

Something about this code was bothering clang in 10.9's developer tools.
Since we're tending to prefer written loops to STL algorithms these days
anyway, rewrite it.
config:  Fix endian.h include guard macro
MacVFS:  Don't override gestalt_device::GetFile()

Just pass the node into the gestalt_device filehandle.
relix:  Add relix::root() as alias of vfs::root()
vfs+:  Pass root node to path resolution functions

Pass the root directory node into every path resolution call, instead of
relying on global state.

Breaks: freemount/8a9483975749bacf059e..091720365d380c1d470c
relix, Genie:  vfs::root() -> relix::root()
Rename vfs::root() to relix::root()
Merge branch 'root'