enable sanitizers on x86_64-linux releases

Author: Jorge Aparicio

src/ci/docker/dist-x86-linux/Dockerfile

@@ -76,5 +76,5 @@ RUN curl -L https://api.pub.build.mozilla.org/tooltool/sha512/$SCCACHE_DIGEST |
 ENV HOSTS=i686-unknown-linux-gnu
 ENV HOSTS=$HOSTS,x86_64-unknown-linux-gnu
 
-ENV RUST_CONFIGURE_ARGS --host=$HOSTS --enable-extended
+ENV RUST_CONFIGURE_ARGS --host=$HOSTS --enable-extended --enable-sanitizers
 ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS