Use cargo to build the build system binary

Author: GuillaumeGomez

y.sh

@@ -2,6 +2,7 @@
 
 set -e
 echo "[BUILD] build system" 1>&2
-mkdir -p build_system/target
-rustc build_system/src/main.rs -o build_system/target/y -Cdebuginfo=1 --edition 2021
-exec ./build_system/target/y "$@"
+cd build_system
+cargo build --release
+cd ..
+./build_system/target/release/y $@