gnucash maint: Multiple changes pushed

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/574f567b (commit)
	 via  https://github.com/Gnucash/gnucash/commit/d7eae066 (commit)
	from  https://github.com/Gnucash/gnucash/commit/8e4c4948 (commit)



commit 574f567b625d3a175ba153bb1c63a0d14e8dd75a
Author: John Ralls <jralls at ceridwen.us>
Date:   Tue Sep 14 09:32:12 2021 -0700

    Refactor GncXmlBackend::get_file_lock.
    
    Moving all of the error-handling to it for better clarity and
    simplicity. Drop the unnecessary stat call, open will fail with
    EEXIST if there's already a lock file. Provide specific messages
    for file system failures.

commit d7eae0664fb4cf7f3411c8d3b47cef32ad2346fc
Author: John Ralls <jralls at ceridwen.us>
Date:   Sun Sep 12 13:29:10 2021 -0700

    [gz_open] Use compress and write consistent with calling functions.



Summary of changes:
 libgnucash/backend/xml/gnc-xml-backend.cpp | 58 ++++++++++++------------------
 libgnucash/backend/xml/gnc-xml-backend.hpp |  2 +-
 libgnucash/backend/xml/io-gncxml-v2.cpp    | 22 ++++++------
 3 files changed, 35 insertions(+), 47 deletions(-)