Electron Releases

Description of Change

Fixes #53200

• Pango 1.52+ spawns a [pango] fontconfig thread that calls FcInit() as soon as GTK creates its font map, and that races the main thread's own first fontconfig call during toolkit initialization. Both parse the configuration at once and corrupt fontconfig's global state; it later surfaces as a PartitionAlloc freelist check (SIGTRAP, #53200) or a NULL dereference inside expat (microsoft/vscode#322185). Upstream: pango#784, pango#872.
• Initialize the system fontconfig once on a helper thread that runs while the Node.js environment is created and is joined before any app code runs, so both later FcInit() calls return immediately. Nothing else touches fontconfig or calls setenv during that window. Resolved via dlsym because the binary also contains Chromium's bundled fontconfig with hidden visibility, which is a separate copy with separate state (that is also why gfx::GetGlobalFontConfig() in gtk_ui.cc does not prevent this).
• If the app's main script changed FONTCONFIG_FILE, FONTCONFIG_PATH or FONTCONFIG_SYSROOT, reload the configuration after the join so GTK still sees what the app asked for.

Main-thread cost, measured with a temporary log around the join (Testing build, Xvfb, warm cache, 8 launches):

Checklist

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Release Notes

Notes: Fixed an intermittent crash at startup on Linux caused by a race between Pango and the main thread initializing fontconfig.