libports: less noisy fuse_ext2 compilation
libports: less noisy libext2fs compilation
libports: less noisy compilation of libfuse

Out of laziness we only provide two dummy functions for all FUSE
operations, which are used in case the FUSE file system does not
implement them itself.
libports: add libc_fuse_ntfs-3g
libports: initial fuse_fs implementation
libports: allow to check FUSE fs initialization

This changes the private API of the FUSE implementation. The init_fs
method now has to return true if the initialization was successful and
otherwise false. All current users of the API are also changed
accordingly.
ports: simple file system test running in noux

By running one of these run scripts a user-defined shell script will
be executed within in noux, which conducts the defined file systems
tests for given File_system_session based file system.
noux: add block device file system

Access to a block session is provided by using the block file system.
By specifying the label, each block session request can be routed to
the proper block session provider:

! <fstab>
! 	...
! 	<dir name="dev">
! 		<block name="blkdev0" label="block_session_0" />
! 	</dir>
! 	...
! </fstab>

In addition to this file system, support for the DIOCGMEDIASIZE ioctl
request was added. This request is used by FreeBSD and therefore our
libc to query the size of the block device in bytes.
noux: add e2fsprogs-v1.42.9 package
noux: add mkfs test scenario
os: add read-only option part_blk XXX

XXX this change only prevents part_blk from setting the operation of
Packet_descriptor::WRITE.
libc: add support for sysconf(_SC_PAGESIZE)