gnucash stable: Multiple changes pushed

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/331fbf3d (commit)
	 via  https://github.com/Gnucash/gnucash/commit/94c343fb (commit)
	 via  https://github.com/Gnucash/gnucash/commit/d7624ab7 (commit)
	from  https://github.com/Gnucash/gnucash/commit/acfc8e6e (commit)



commit 331fbf3dec561b3973d4ffce60f36959feeb9dc1
Merge: acfc8e6ec9 94c343fb5f
Author: John Ralls <jralls at ceridwen.us>
Date:   Thu Jun 12 16:52:55 2025 -0700

    Merge John Ralls's branch 'bug799521' into stable

commit 94c343fb5f3f753b151bf76dc59584466e5390f2
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat May 31 14:52:54 2025 -0700

    Bug 799521 - Segmentation fault on Autocomplete of Description with ß
    
    Replace GLib UTF-8 normalize and casefold comparison with
    gnc_unicode_has_substring_base_chars and use
    gnc_unicode_compare_base_chars for the exact match
    comparison. gnc_unicode_has_substring_base_chars is able to capture the
    correct length of the match in source string and so avoids the buffer
    overrun when applying the casefolded substring to the source
    string. Both functions compare the strings for equivalence correctly
    for the current locale, which casefolded comparison didn't do well.

commit d7624ab75cb5f1b7de2e7449a12513b22aeaa921
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat May 31 13:32:09 2025 -0700

    [Core Utils] Add ICU-based substring search.
    
    See
    https://unicode-org.github.io/icu/userguide/collation/string-search.html
    for a discussion of ICU's string search capabilities. This new file
    implements finding substrings and string comparisons at all but the
    quaternary strength, that being of somewhat rarefied utility.



Summary of changes:
 CMakeLists.txt                                     |   2 +-
 .../register/register-gnome/completioncell-gnome.c |  58 ++----
 libgnucash/core-utils/CMakeLists.txt               |   3 +
 libgnucash/core-utils/gnc-unicode.cpp              | 220 +++++++++++++++++++++
 libgnucash/core-utils/gnc-unicode.h                | 144 ++++++++++++++
 libgnucash/core-utils/test/CMakeLists.txt          |  18 +-
 libgnucash/core-utils/test/gtest-gnc-unicode.cpp   | 135 +++++++++++++
 po/POTFILES.in                                     |   1 +
 8 files changed, 534 insertions(+), 47 deletions(-)
 create mode 100644 libgnucash/core-utils/gnc-unicode.cpp
 create mode 100644 libgnucash/core-utils/gnc-unicode.h
 create mode 100644 libgnucash/core-utils/test/gtest-gnc-unicode.cpp