I can confirm the issue on a VM with macOS. The error appears in unit reglddfeatures of the LazDataDesktop project (it is in the tools folder of the Lazarus installation, Gus). The guilty unit is surrounded by an {$IFDEF HAVEMYSQL5657CONN} directive. So, go to the head of this unit, find the {$DEFINE HAVEMYSQL5657CONN} and undefine it by putting a space or a dot between the { and the $. There's another define, {$DEFINE HAVEMSSQLCONN} which must be handled in the same way. After these modifications, the LazDataDesktop compiles correctly.