Add XUI localization support with Swedish translations

[yeager]

Summary

• initialize gettext for the XUI HUD/menu path
• add XUI source files and custom widget helpers to gettext extraction
• mark core XUI menu, settings, notification, update, snapshot, and compatibility-reporting strings for translation
• update Swedish translations for the newly extracted strings

Tests

• xgettext --from-code=UTF-8 --language=C++ --keyword=_ --keyword=N_ --keyword=C_:1c,2 --keyword=NC_:1c,2 --keyword=g_dcgettext:2 --keyword=g_dngettext:2,3 --keyword=g_dpgettext2:2c,3 --keyword=SectionTitle:1 --keyword=Toggle:1 --keyword=Slider:1 --keyword=FilePicker:1 --keyword=PopupMenuButton:1 --keyword=PopupMenuSubmenuButton:1 --keyword=PopupMenuToggle:1 --msgid-bugs-address=qemu-devel@nongnu.org -f po/POTFILES -o /tmp/xemu.pot
• msgmerge --backup=off --update po/sv.po /tmp/xemu.pot
• msgfmt --check-format --check-domain -o /dev/null po/sv.po

A local compile was not completed because this machine does not have the required libpcap pkg-config dependency installed; Meson stops before generating build targets.

[gemini-code-assist]

Code Review

This pull request implements internationalization (i18n) for the XUI interface by introducing a gettext-based translation system, updating the build configuration, and wrapping UI strings in the translation macro. Feedback focuses on optimizing string extraction by updating xgettext keywords in the build system to include widget descriptions, which would eliminate the need for redundant manual translation wraps in the UI code.

[gemini-code-assist]

The Toggle and Slider widgets both take a description string as their third argument. To ensure these strings are automatically extracted by xgettext without needing manual _() wrapping at every call site, you should update the keyword definitions to include the third argument (e.g., Toggle:1,3).

                 '--keyword=Toggle:1,3',
                 '--keyword=Slider:1,3',

[gemini-code-assist]

Since the Toggle implementation in widgets.cc already calls _() on the description argument, wrapping it in _() here is redundant and leads to double translation lookups at runtime. Once the xgettext keywords in po/meson.build are updated to include the third argument, these manual wraps can be removed for better consistency with how titles are handled.

    Toggle("Check for updates", &g_config.general.updates.check,
           "Check for updates whenever xemu is opened");

[gemini-code-assist]

Redundant _() wrapping for the description argument. See previous comment regarding Toggle keyword extraction and internal translation.

    Toggle("Hard FPU emulation", &g_config.perf.hard_fpu,
           "Use hardware-accelerated floating point emulation (requires restart)");

[gemini-code-assist]

Redundant _() wrapping for the description argument.

    Toggle("Cache shaders to disk", &g_config.perf.cache_shaders,
           "Reduce stutter in games by caching previously generated shaders");

[gemini-code-assist]

Redundant _() wrapping for the description argument.

    Toggle("Skip startup animation", &g_config.general.skip_boot_anim,
           "Skip the full Xbox boot animation sequence");

[gemini-code-assist]

Redundant _() wrapping for the description argument.

    if (Toggle("Fullscreen", &fs, "Enable fullscreen now")) {

[mborgerson]

Do you plan to test any of your changes?

[yeager]

Tested the XUI localization path on Fedora 43 (Burken2) with a fresh local build of the updated PR branch.

Build/test notes:

• Built commit 0e9eaac on Fedora 43
• Ran xemu under Xvfb with Swedish locale:
  • LANG=sv_SE.UTF-8
  • LC_ALL=sv_SE.UTF-8
  • LANGUAGE=sv
• Verified the runtime loads Swedish XUI strings from qemu.mo
• Verified the previously half-English settings/input views are now localized

Screenshots are attached to this comment only; they are not stored in the repository.

[yeager]

Follow-up from screenshot review: fixed remaining untranslated XUI settings/menu text visible in the Swedish UI.

Changes:

• Localized main settings navigation tabs: General/Input/Display/Audio/Network/System/About
• Localized System settings labels, descriptions, combo previews, and file picker labels
• Localized Input settings values/messages such as Xbox Controller, Not Connected, and the empty input-device prompt
• Made chevron combo preview/items pass through gettext at render time
• Added extraction keywords for XUI tab buttons and chevron combo labels/descriptions

Validation:

• msgfmt --check-format --check-domain -o /tmp/xemu-sv.mo po/sv.po
• Fedora 43 rebuild: make -C build -j2 qemu-system-i386
• Ran under Xvfb with LANG=sv_SE.UTF-8, LC_ALL=sv_SE.UTF-8, LANGUAGE=sv

Screenshots were used for validation only and are not stored in the repository.