add cargo settings

.cargo/config.toml

@@ -0,0 +1,13 @@
+[profile.dev]
+opt-level = 1
+
+[profile.dev.package."*"]
+opt-level = 3
+
+[target.x86_64-unknown-linux-gnu]
+linker = "clang"
+rustflags = ["-C", "target-cpu=native", "-C",
+	"link-arg=-fuse-ld=/usr/bin/mold"]
+
+[build]
+rustc-wrapper = "sccache"