I have latest SVN version.
First of all, `USE_SSL` is uncommented by default in defs.inc so a user has to edit defs file otherwise he can't control this option.
Second, without `USE_SSL` ICS packages couldn't be built as following units have incorrect defines sections:
OverbyteIcsSslX509Utils in '..\Source\OverbyteIcsSslX509Utils.pas',
OverbyteIcsLibeayEx in '..\Source\OverbyteIcsLibeayEx.pas',
OverbyteIcsProxy in '..\Source\OverbyteIcsProxy.pas',
OverbyteIcsSslJose in '..\Source\OverbyteIcsSslJose.pas',
OverbyteIcsSslHttpRest in '..\Source\OverbyteIcsSslHttpRest.pas',
OverbyteIcsSslX509Certs in '..\Source\OverbyteIcsSslX509Certs.pas',
OverbyteIcsIpStreamLog in '..\Source\OverbyteIcsIpStreamLog.pas',
OverbyteIcsMailQueue in '..\Source\OverbyteIcsMailQueue.pas',
OverbyteIcsHttpMulti in '..\Source\OverbyteIcsHttpMulti.pas',
OverbyteIcsFtpMulti in '..\Source\OverbyteIcsFtpMulti.pas',
Third, unit `OverbyteIcsHttpAppServer` can't be built as well as it uses `ClientCnx.HostTag` that is unavailable without SSL
Fourth, `TSslWSocketClient` has `TriggerSslAlpnSelect` overridden method that is not virtual in base `TWSocketClient` so compiler produces build failure.