message: use packed C structs to be compatible to the proxy
diff: @@ -114,7 +114,7 @@ fn setup_connection(fd: i32) {
  // once https://github.com/rust-lang/rfcs/blob/master/text/2195-really-tagged-unions.md
  // has been implemented.
  //
  -#[repr(C)]
  +#[repr(C, packed)]
  struct SysWrite {
  sysnr: i32,
  fd: i32,
  @@ -131,7 +131,7 @@ impl SysWrite {
  }
  }
  -#[repr(C)]
  +#[repr(C, packed)]
  struct SysClose {
  sysnr: i32,
  fd: i32
  @@ -146,7 +146,7 @@ impl SysClose {
  }
  }
  -#[repr(C)]
  +#[repr(C, packed)]
  struct SysOpen {
  sysnr: i32
  }
  @@ -159,7 +159,7 @@ impl SysOpen {
  }
  }
  -#[repr(C)]
  +#[repr(C, packed)]
  struct SysExit {
  sysnr: i32,
  arg: i32
  @@ -174,7 +174,7 @@ impl SysExit {
  }
  }
  -#[repr(C)]
  +#[repr(C, packed)]
  struct SysRead {
  sysnr: i32,
  fd: i32,
  @@ -191,7 +191,7 @@ impl SysRead {
  }
  }
  -#[repr(C)]
  +#[repr(C, packed)]
  struct SysLseek {
  sysnr: i32,
  fd: i32,
  