Build system will now detect OS and pass it down to build_sdk.sh.

build_sdk.sh will now automatically choose the correct cargo-make command line based on the OS

frontend/scripts/build_sdk.sh

@@ -34,7 +34,7 @@ Windows)
 
 *)
  # All undefined cases
- echo "[ERROR] The FLOWY_DEV_ENV environment variable must be set. Please see the GitHub wiki for instructions."
+ echo "[ERROR] The FLOWY_DEV_ENV environment variable must be set. Please see the GitHub wiki for build instructions."
  exit 1
  ;;
 esac