Update FreeBSD network drivers with the 9.3 release
Remove unnecessary zlib build feature dependency
BPositionIO: Add {Read,Write}AtExactly()

Analoguous to {Read,Write}Exactly(), just for the *At() versions.
Add private class BFdIO

Simple BPositionIO implementation using the POSIX API on a FD. In effect
similar to BFile, but more easily ported to kernel and boot loader (and
the FD is reusable).
boot loader: Add pwrite(), lseek(), ftruncate()

ftruncate() is just a stub (needed for BFdIO).
Switch package file accessor classes to use BPositionIO

* PackageFileHeap{Reader,Writer} as well as Package{Reader,Writer} and
  their implementation and super classes do now internally use a
  BPositionIO instead of a FD to access the package file. This provides
  more flexibility needed for features to come.
* BPackageReader has already grown a new Init() version with a
  BPositionIO* parameter.
Increase boot loader size for x86* boot floppy a bit
package kit: Actually add support for B_HPKG_COMPRESSION_NONE

Until now we always declared in the HPKG header that the package file is
zlib compressed. For uncompressed files we would just store all
individual chunks uncompressed. Now we handle completely uncompressed
files slightly differently: We don't write the redundant chunk size
table anymore. The size savings are minor, but it makes the uncompressed
format read-streamable which may be handy.
package: Explicitly use B_HPKG_COMPRESSION_NONE
Fix building Haiku from Haiku

* Always include cdefs.h to have __[BEGIN|END]_DECLS defined.
  Somehow, this didn't affect cross-build, but it made building
  from Haiku fail.
Move libroot synchronization functions to private namespace

* Prefix lock functions with __ to mark them as private. Add
  forwarding macros to keep existing code working.

* Avoids symbol name clashes with kernel lock APIs, occuring when
  using kernellandemu-lib in userlandfs. Thanks to Ingo for the
  suggestion.
BPackageWriter: Add BPositionIO support
Add private BDataPositionIOWrapper

Implements the BPositionIO interface on top of a BDataIO, requiring the
{Read,Write}At() accesses to be sequential.
ReaderImplBase::Init(): Make file size check optional

If the file doesn't support GetSize(), skip the header total size file
size check.
package recompress: Add stdin/stdout support

stdin doesn't work quite yet. We'll need to convince the BPackageReader
to skip parsing the TOC and package attributes sections.
PackageReaderImpl: Delay reading sections until ParseContent()
BPackageWriter::Recompress(): Change param to BPositionIO*

Besides that this is a nicer interface, it allows us to get a the HPKG
header as a side effect of initializing the reader, thus preventing
seeking backward in the file. This makes "package recompress - <file>"
work.
package recompress: Small cleanup
package: Add checksum command
clean up files unrelated to the FreeBSD 9.3 driver update.