mount.c: fix mount option for exfat

Fixed HTTP boot when server sent more headers after Content-Length (closes: #41072)

Support booting complete ISOs via HTTP (closes: #40710)

Figure out stage2 size at the run time instead of relying on

Improved IO errors handling when loading stage2 (closes: #40803)
Support loading stage2 images >= 2GB (related: #40710)

When mounting a cifs share try older protocol versions (related: #40554)
Log messages to ttyprintk for easier debugging

Network boot: automatically select interface with a carrier (closes: #40616)

Avoid deadlock between udev probing stage2 and stage1 mounting it (closes: #40687)

mkmodpack: include leading directories for firmware files

Add support 'fuid' automatic mode option for method cdrom
Fix potential memory overflow in welcome string
Set PREFIX to "/" for nfs and cifs methods due its mounted to image root

cdrom.c: Try to mount multiple devices in automatic mode

disk.c, mount.c: Add support exfat

mkmodpack: warn about incorrect patterns

fix hangs until http socket not closed on server side (closes: #37150)
tools.c: break reading cycle if we actually loaded program into memory
url.c, network.c: disable keep-alive and close http socket after downloading

compile with _FILE_OFFSET_BITS=64

probing.c: added support for SD-cards when boot in LiveCD-mode