How can we use pre-compiled commands to determine the Delphi version?

Use {$ ifdef ver1xx} to determine

// Delphi 4
{$ Ifdef ver120}
{$ Define vcl4orabve}
{$ Define vcl4o}
{$ Define Delphi}
{$ Define delphi4}
{$ Define overloading}
{$ Define optionalparams}
{$ Endif}

// C ++ Builder 4
{$ Ifdef ver125}
{$ Define vcl4orabve}
{$ Define vcl4o}
{$ Define cbuilder}
{$ Define cbuilder4}
{$ Define overloading}
{$ Define optionalparams}
{$ Endif}

// Delphi 5 & cbuilder 5
{$ Ifdef ver130}
{$ Define vcl4orabve}
{$ Define vcl5orabve}
{$ Define vcl5o}
{$ Ifdef BCB}
{$ Define cbuilder}
{$ Define cbuilder5}
{$ Else}
{$ Define Delphi}
{$ Define delphi5}
{$ Endif}
{$ Define overloading}
{$ Define optionalparams}
{$ Define sametext}
{$ Endif}

// Delphi 6
{$ Ifdef ver140}
{$ Define vcl4orabve}
{$ Define vcl5orabve}
{$ Ifdef BCB}
{$ Define cbuilder}
{$ Define cbuilder6}
{$ Else}
{$ Define Delphi}
{$ Define DELPHI6}
{$ Endif}
{$ Define overloading}
{$ Define optionalparams}
{$ Define sametext}
{$ Define vcl6orabve}
{$ Define vcl6o}
{$ Endif}

// Delphi 7
{$ Ifdef ver150}
{$ Define vcl4orabve}
{$ Define vcl5orabve}
{$ Ifdef BCB}
{$ Define cbuilder}
{$ Define cbuilder7}
{$ Else}
{$ Define Delphi}
{$ Define Delphi7}
{$ Endif}
{$ Define overloading}
{$ Define optionalparams}
{$ Define sametext}
{$ Define vcl6orabve}
{$ Define vcl7orabve}
{$ Define vcl6o}
{$ Define vcl70}
{$ Endif}

// Delphi 8
{$ Ifdef ver160}
{$ Define vcl4orabve}
{$ Define vcl5orabve}
{$ Ifdef BCB}
{$ Define cbuilder}
{$ Define cbuilder8}
{$ Else}
{$ Define Delphi}
{$ Define delphi8}
{$ Endif}
{$ Define overloading}
{$ Define optionalparams}
{$ Define sametext}
{$ Define vcl6orabve}
{$ Define vcl7orabve}
{$ Define vcl80rabove}
{$ Define vcl6o}
{$ Define vcl70}
{$ Define vcl80}
{$ Endif}

// Delphi 9
{$ Ifdef ver170}
{$ Define vcl4orabve}
{$ Define vcl5orabve}
{$ Ifdef BCB}
{$ Define cbuilder}
{$ Define cbuilder9}
{$ Else}
{$ Define Delphi}
{$ Define delphi9}
{$ Endif}
{$ Define overloading}
{$ Define optionalparams}
{$ Define sametext}
{$ Define vcl6orabve}
{$ Define vcl7orabve}
{$ Define vcl80rabove}
{$ Define vcl9orabve}
{$ Define vcl6o}
{$ Define vcl70}
{$ Define vcl80}
{$ Define vcl90}
{$ Endif}

// Delphi 10
{$ Ifdef ver180}
{$ Define vcl4orabve}
{$ Define vcl5orabve}
{$ Ifdef BCB}
{$ Define cbuilder}
{$ Define cbuilder10}
{$ Else}
{$ Define Delphi}
{$ Define delphi10}
{$ Endif}
{$ Define overloading}
{$ Define optionalparams}
{$ Define sametext}
{$ Define vcl6orabve}
{$ Define vcl7orabve}
{$ Define vcl80rabove}
{$ Define vcl9orabve}
{$ Define vcl1o0rabove}
{$ Define vcl6o}
{$ Define vcl70}
{$ Define vcl80}
{$ Define vcl90}
{$ Define vcl100}
{$ Endif}

{$ Ifdef Linux}
{$ Define vcl4orabve}
{$ Define vcl5orabve}
{$ Define overloading}
{$ Define optionalparams}
{$ Define sametext}
{$ Define vcl6orabve}
{$ Define vcl6o}
{$ UNDEF DELPHI6}
{$ Define kylix}
{$ Ifdef conditionalexpressions}
{$ 'If rtlversion = 14.0}
{$ Define kylix2}
{$ Ifend}
{$ 'If rtlversion = 14.50}
{$ Define kylix3}
{$ Ifdef BCB}
{$ Define bcbkylix3}
{$ Endif}
{$ Ifend}
{$ 'If rtlversion = 15.0}
{$ Define kylix4}
{$ Ifend}
{$ Endif}
{$ Endif}