* Fix ARM64 build from linked-build (self-built SDK) - debian/patches/fix-glibc-2.40-TLS-crash-in-CLR-signal-handlers.patch: disable FEATURE_HIJACK on Linux arm64 to work around glibc >= 2.40 TLS crash in signal handler (dotnet/runtime#121581); the self-built SDK was crashing at startup when used as Build-Depends in linked builds; GC uses polling instead of signal-based thread hijacking - debian/patches/fix-build-server-shutdown-ignore-exit-code.patch: ignore exit code of 'dotnet build-server shutdown' which fails when the VB/C# compiler server was never started (UseSharedCompilation=false) - debian/patches/fix-nuget-config-duplicate-package-source-mappings.patch: remove duplicate packageSourceMapping entries in NuGet.config generated by UpdateNuGetConfigPackageSourcesMappings task during online builds - debian/patches/fix-nuget-client-skip-config-rename-patch.patch: add --allow-empty and IgnoreExitCode to git apply in nuget-client source-build; the NuGet.Config rename patch fails on case-sensitive Linux filesystems where the file is already lowercase - debian/rules: use CC=clang CXX=clang++ to avoid GCC 14 codegen issues with libcoreclr.so on arm64; set GLIBC_TUNABLES=glibc.rtld.optional_ static_tls=4096 to work around glibc 2.40 TLS allocation bug; disable -mbranch-protection via hardening=-branch