Disable ThinLTO for x86_64-unknown-linux-gnu

Temporarily addresses #76980.

Author: Mark-Simulacrum

src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile

@@ -95,7 +95,7 @@ ENV RUST_CONFIGURE_ARGS \
       --set target.x86_64-unknown-linux-gnu.linker=clang \
       --set target.x86_64-unknown-linux-gnu.ar=/rustroot/bin/llvm-ar \
       --set target.x86_64-unknown-linux-gnu.ranlib=/rustroot/bin/llvm-ranlib \
-      --set llvm.thin-lto=true \
+      --set llvm.thin-lto=false \
       --set llvm.ninja=false \
       --set rust.jemalloc
 ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS