rm -rf /tmp/rustc-pgo
-python2.7 ../x.py build --target=$PGO_HOST --host=$PGO_HOST \
+python3 ../x.py build --target=$PGO_HOST --host=$PGO_HOST \
--stage 2 library/std --rust-profile-generate=/tmp/rustc-pgo
RUSTC_BOOTSTRAP=1 ./build/$PGO_HOST/stage2/bin/rustc --edition=2018 \