Add more robust generic attribute emulation variant

The new configure option "--use-xattr-ref" enables an xattr assisted
variant of the generic attribute emulation. Instead of using the inode
ID of a node to identify its attribute directory, we use a reasonably
unique random 128 bit number, which we generate and attach as an
attribute to the node. This way, when a node changes its inode ID
(defragmentation?) or the inode ID of a removed node with a left-over
attribute directory is reused, attributes won't get mixed up.

The old method is still used for symlinks (since on Linux only
priviledged users can write attributes on symlinks), but those usually
only have a rather boring BEOS:TYPE attribute, so mix-ups wouldn't be
that problematic anyway.

CID 701957: opendir() NULL returns weren't accounted for.

* BuildPlatformMain supports overriding HOST_LIBROOT on the target now,
so one can set it to the static libroot, if desired.
* Generic attribute emulation:
- Added build tool rm_attrs, a simple "rm" replacement, which also
removes the attributes directory for a given file.
- Added build/scripts/rm_attrs shell script, which wraps the
invocation of the rm_attrs tool. If it doesn't exist yet, the
ordinary rm is used.
- The RM jam variable refers to the rm_attrs script now, i.e. whenever
something is removed by the build system, the attributes are removed
too (if the build tool has already been built, that is).
- Removed the shell function attrrmrf() in build_haiku_image. We use
the rm_attrs tool instead, if necessary.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24528 a95241bf-73f2-0310-859d-f6bbb57e9c96

Add more robust generic attribute emulation variant

The new configure option "--use-xattr-ref" enables an xattr assisted
variant of the generic attribute emulation. Instead of using the inode
ID of a node to identify its attribute directory, we use a reasonably
unique random 128 bit number, which we generate and attach as an
attribute to the node. This way, when a node changes its inode ID
(defragmentation?) or the inode ID of a removed node with a left-over
attribute directory is reused, attributes won't get mixed up.

The old method is still used for symlinks (since on Linux only
priviledged users can write attributes on symlinks), but those usually
only have a rather boring BEOS:TYPE attribute, so mix-ups wouldn't be
that problematic anyway.

CID 701957: opendir() NULL returns weren't accounted for.

* BuildPlatformMain supports overriding HOST_LIBROOT on the target now,
so one can set it to the static libroot, if desired.
* Generic attribute emulation:
- Added build tool rm_attrs, a simple "rm" replacement, which also
removes the attributes directory for a given file.
- Added build/scripts/rm_attrs shell script, which wraps the
invocation of the rm_attrs tool. If it doesn't exist yet, the
ordinary rm is used.
- The RM jam variable refers to the rm_attrs script now, i.e. whenever
something is removed by the build system, the attributes are removed
too (if the build tool has already been built, that is).
- Removed the shell function attrrmrf() in build_haiku_image. We use
the rm_attrs tool instead, if necessary.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24528 a95241bf-73f2-0310-859d-f6bbb57e9c96