Change in flashrom[master]: flashrom.c: Implement file-based locking semantics

[Thomas Heijligen (Code Review)]

Attention is currently required from: Hung-Te Lin, Nico Huber, Subrata Banik, Edward O'Callaghan, Daniel Campello.
Thomas Heijligen has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/62213 )

Change subject: flashrom.c: Implement file-based locking semantics
......................................................................

Patch Set 25:

(1 comment)

Patchset:

PS25: 
A few things that feel not good about this implementation:
 - (lib)flashrom supports systems with a limited filesystem implementation. (libpayload)
 - unistd.h may not be available on some platforms (DJGPP/DOS)
 - The filelock paths are not run Windows compatible
 - It prevent the usage of multiple different programmer at the same time (e.g. usb / ftdi)

IMO we have to look closer when the use of a lock is wise and not try to lock in any case.