[syslinux] A Few Syslinux 5.00-pre9 Bugs

[Shao Miller]

Just a few bug-reports, before I forget:

- A Windows installer bug for 4.06 and presumably 5.00-pre9 whereby the ADV
contains backslashes.  Reproduced with: syslinux.exe --directory \two\dirs
e:

- An open() (?) bug for 4.06 and presumably 5.00-pre9 whereby the filename
/ubcd/custom/syslinux-5.00-pre9/com32/gplinclude/acpi/facs.h fails to open()
after 134 iterations in a loop where it's closed after each open()  Variant
was ISOLINUX.

- A PXELINUX 5.00-pre9 bug whereby linux.c32 fails to load a 70 MB file with
1024 MiB RAM (in QEmu).  The same scenario with ISOLINUX is fine.  Possibly
worth noting is that this was iPXE (ipxe.pxe) -> PXELINUX 5.00-pre9 using
HTTP for the large file.  (TFTP untested.)

- A bug for 4.06 and presumably 5.00-pre9 whereby chain.c32 can no longer
chain Win98 DOS with: hd0,1 msdos=io.sys  Chaining boot-sector files made by
SYS.COM is fine.

- Shao Miller (not a bug)