Command line used to compile System.pas in Delphi
dcc32.exe -$C- -$D0 -$L- -CG -H -M -Q -V- -W^ -Z --no-config -JPHN -W-UNSUPPORTED_CONSTRUCT -W-UNIT_DEPRECATED -W-SYMBOL_DEPRECATED -W-UNIT_PLATFORM -W-SYMBOL_PLATFORM -W-WIDECHAR_REDUCED -R%BDS%\lib\win32\release -U%BDS%\lib\win32\release -O%BDS%\lib\win32\release -NU%BDS%\lib\win32\release -NH%BDS%\include\windows\rtl\win32 -NO%BDS%\lib\win32\release -M -y System.pas
dcc32.exe -$C- -$D2 -CG -H -M -Q -V- -W^ -Z --no-config -JPHN -W-UNSUPPORTED_CONSTRUCT -W-UNIT_DEPRECATED -W-SYMBOL_DEPRECATED -W-UNIT_PLATFORM -W-SYMBOL_PLATFORM -W-WIDECHAR_REDUCED -R%BDS%\lib\win32\debug -U%BDS%\lib\win32\debug -O%BDS%\lib\win32\debug -NU%BDS%\lib\win32\debug -NH%BDS%\include\windows\rtl\win32 -NO%BDS%\lib\win32\debug -M -y System.pas
In 2017, with the release of Delphi 10.2 Tokyo, Embarcadero introduced a specialized implementation of the Observer pattern into the System.Classes unit. While it has been in the wild for 9 years, it remains a "hidden" architecture for many, primarily because it serves as the invisible engine behind LiveBindings. Other than live bindings, you can also use the Observer pattern as a way to update component settings to the Windows registry, an .ini file, or persist it elsewhere.
System.Classes