+# // Modifying just rustc?
+# // Compile rustc+libstd once
+# make rustc-stage1
+# // From now on use this command to rebuild just rustc and reuse the previously built libstd
+# // $host is a target triple, eg. x86_64-unknown-linux-gnu
+# // The resulting binary is located at $host/stage1/bin/rustc.
+# // If there are any issues with libstd recompile it with the command above.
+# make $host/stage1/bin/rustc
+#