Enchant looks for its providers (including the WinSpell spellcheck
provider) under a hardcoded default path derived from its build
prefix, which is C:\gtk-build\gtk\x64\release\lib\enchant-2 when
built via gvsbuild. After installation, the provider DLLs live
under ZoiteChat's own install directory, so Enchant fails to find
them and spellcheck silently stops working.
Call enchant_set_prefix_dir() to redirect Enchant's provider search
to <install_dir> before the first enchant_broker_init().
enchant_set_prefix_dir() expects the installation prefix itself;
Enchant adds lib\enchant-2 when searching for providers.
The symbol is loaded optionally since it may not exist in older
Enchant builds; if missing, behavior is unchanged.
Require Enchant 2.8.19 or newer so Windows can use upstream winspell.
Remove the in-tree libenchant_win8 provider project and sources.
Update runtime library probing to prefer Enchant 2 library names.