[Lazarus] Trunk compilation broken by changing StrikeThrough property name

[Bart]

This part:

  {$IF FPC_FULLVERSION>=20601} //changed in 2.6.2 and 2.7; remove when
FPC 2.6.2+ only is supported
  Font.StrikeThrough := AFont.StrikeThrough;
  {$ELSE}
  Font.StrikeTrough := AFont.StrikeTrough; //old version with typo
  {$ENDIF}

will make it stop working with the 2.6.2RC1 version too, since  it's
fullversion = 20602

As a quick fix, can we change that to:

  {$IF (FPC_FULLVERSION<20600) or defined(lazcanvas_typo)} //changed
in 2.6.2 and 2.7; remove when FPC 2.6.2+ only is supported
  Font.StrikeTrough := AFont.StrikeTrough; //old version with typo
  {$ELSE}
  Font.StrikeThrough := AFont.StrikeThrough;
  {$ENDIF}

This will allow 2.6.2RC1 users to define lazcanvas_typo when building
Lazarus, as a temporary workaround.

Bart