Add syslog output support to bootloader

Broadcast console output as syslog debug messages, stripped of trailing newlines.
Disabled by default.

Patch from #6168.

Change-Id: I1754381477dcde00bdcfa4482017daf5eb682cd3
Reviewed-on: https://review.haiku-os.org/c/912
Reviewed-by: Stephan Aßmus <superstippi@gmx.de>

boot loader: Almost removed use of kernel_cpp.h.

* For some reason that is beyond me, fat/CachedBlock.cpp needs this header,
or else building the boot loader fails.

* Added Directory::CreateFile() which can be implemented by file systems to
support file creation.
* Extended open() and open_from() to support O_CREAT to create files.
open_from() has got an optional "permissions" parameter for that purpose.
* Fixed errno. It would crash when being used. Also changed the POSIX functions
to return their error code via errno as expected.
* Added writev().
* FAT file system:
- Added support for reading long file names.
- Added support for creating files (8.3 name only) and writing to them.
- Enabled scanning partitions with it.
* Boot loader menu:
- Enabled the "Reboot" menu item unconditionally.
- Added "Save syslog from previous session" menu item to the debug menu.
Currently saving the syslog to FAT32 volumes is supported.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35882 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Fixed the semantics of [v]snprintf(): If the buffer is not large enough,
the function shall nevertheless return the length of the string that would
be written, if the buffer were large enough.
Added a touch of C++ while doing that. :-)
* Fixed the instances in boot loader, kernel, and kernel modules where the
wrong semantics were expected. The majority of uses actually.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34826 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixed fputc() for the PPC platform (would only write null bytes due to
big endian).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@16090 a95241bf-73f2-0310-859d-f6bbb57e9c96

Renamed src/kernel to src/system.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12359 a95241bf-73f2-0310-859d-f6bbb57e9c96

boot loader: Almost removed use of kernel_cpp.h.

* For some reason that is beyond me, fat/CachedBlock.cpp needs this header,
or else building the boot loader fails.

* Added Directory::CreateFile() which can be implemented by file systems to
support file creation.
* Extended open() and open_from() to support O_CREAT to create files.
open_from() has got an optional "permissions" parameter for that purpose.
* Fixed errno. It would crash when being used. Also changed the POSIX functions
to return their error code via errno as expected.
* Added writev().
* FAT file system:
- Added support for reading long file names.
- Added support for creating files (8.3 name only) and writing to them.
- Enabled scanning partitions with it.
* Boot loader menu:
- Enabled the "Reboot" menu item unconditionally.
- Added "Save syslog from previous session" menu item to the debug menu.
Currently saving the syslog to FAT32 volumes is supported.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35882 a95241bf-73f2-0310-859d-f6bbb57e9c96

* Fixed the semantics of [v]snprintf(): If the buffer is not large enough,
the function shall nevertheless return the length of the string that would
be written, if the buffer were large enough.
Added a touch of C++ while doing that. :-)
* Fixed the instances in boot loader, kernel, and kernel modules where the
wrong semantics were expected. The majority of uses actually.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34826 a95241bf-73f2-0310-859d-f6bbb57e9c96

Fixed fputc() for the PPC platform (would only write null bytes due to
big endian).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@16090 a95241bf-73f2-0310-859d-f6bbb57e9c96

Renamed src/kernel to src/system.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12359 a95241bf-73f2-0310-859d-f6bbb57e9c96