message: Update README.md
  Add autoconf as a necessary step to for Linux platforms
diff: @@ -51,7 +51,7 @@ Additionally, you'll need a C/C++ compiler and the basic dependencies needed for
  To check all dependencies and install missing ones on **Debian/Ubuntu/Mint/etc**:
  - apt install build-essential libssl-dev libevent-dev libseccomp-dev libcap-dev libboost-all-dev pkg-config
  + apt install build-essential libssl-dev libevent-dev libseccomp-dev libcap-dev libboost-all-dev pkg-config autoconf
  # the following commands should only be run if building the GUI wallet
  apt install qtbase5-dev qttools5-dev-tools qtchooser
  