CLSA-2026-1776246056 glib2: Fix of 5 CVEs

CVE-2026-1489: fix integer overflow in Unicode case conversion functions - CVE-2026-1484: fix integer overflow in GLib Base64 encoding - CVE-2026-1485: fix buffer underflow in content type treemagic parsing - CVE-2026-0988: fix integer overflow in gbufferedinputstreampeek - CVE-2025-7039: fix...