gnucash maint: Multiple changes pushed

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/901fea15 (commit)
	 via  https://github.com/Gnucash/gnucash/commit/38cd06e5 (commit)
	 via  https://github.com/Gnucash/gnucash/commit/06652082 (commit)
	 via  https://github.com/Gnucash/gnucash/commit/e4619fda (commit)
	from  https://github.com/Gnucash/gnucash/commit/079a9003 (commit)



commit 901fea158f29f088e2cd9d01041b842b80af1b6f
Merge: 079a90030 38cd06e54
Author: John Ralls <jralls at ceridwen.us>
Date:   Mon Sep 6 15:22:49 2021 -0700

    Merge Simon Arlott's 'xml-locking-fixes' into maint.

commit 38cd06e54a016f6d039ff97ecffaf4c0f8eb7191
Author: John Ralls <jralls at ceridwen.us>
Date:   Mon Sep 6 15:18:34 2021 -0700

    Remove the lock-file-link-count test from the XML backend.
    
    This was an effort of somewhat dubious value to detect if a process
    on another ocmputer had a hsrd-link to a lockfile on an NFS share.
    NFS is rarely used now and SMB doesn't support hard links so this check
    adds complexity with no real value.

commit 066520829970fd14c45f953884e6aeeb7d4e1202
Author: Simon Arlott <sa.me.uk>
Date:   Tue Aug 24 09:01:16 2021 +0100

    xml-backend: Lock file is deleted even if the lock is not acquired
    
    The lock file is set in m_lockfile and then unlinked in session_end even if
    the lock was not acquired.
    
    Clear m_lockfile if locking was not successful.

commit e4619fdae6eeb481faf2385a94a7ba8e21183a0d
Author: Simon Arlott <sa.me.uk>
Date:   Tue Aug 24 08:54:06 2021 +0100

    xml-backend: Don't try to close m_lockfd if it's not open
    
    m_lockfd is not initialised. If the file is locked then it will not be set
    before session_end and close() will be called on an uninitialised int.
    
    Initialise it to -1 in the class definition.
    Consistently use -1 instead of "< 0" or "< 1" as the definition of invalid.
    Always set it to -1 after closing it.



Summary of changes:
 libgnucash/backend/xml/gnc-xml-backend.cpp | 86 +++---------------------------
 libgnucash/backend/xml/gnc-xml-backend.hpp |  2 +-
 2 files changed, 8 insertions(+), 80 deletions(-)