int 25h and int 26h are known to be register-dirty for some versions
of DOS -- unlike int 21h, which is usually clean.  As such, wrap those
in assembly functions.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Always try the FAT32-aware direct I/O calls before trying the legacy
raw I/O calls.  The reason for doing this is that the FAT32 stuff may
be implemented as an add-on.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Fix DOS version 7.10 (first FAT32-capable version) check.

Perhaps we should just call the FAT32 calls blindly and fall back to
the old calls if they fail?

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Code the soft-locking loop correctly.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

The locking API works very different in raw DOS mode and in Windows
mode.  The hierarchial locking is only available in the latter mode;
in the former mode we can only use levels 0 and 4.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

At least under WinME, the DOS installer did not work as advertised.
With these modifications, it seems to work okay.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Automatically reformat dos/syslinux.c using Nindent.

Do this for all files except HDT, gPXE and externally maintained
libraries (zlib, tinyjpeg, libpng).

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Hook up RAID mode in the installers for SYSLINUX