The following compiler directives seem to work in GPC
{$W unused} {$W unused-function} {$W unused-value} {$W unused-parameter} {$W unused-label} {$W unused-variable} {$W unused-function}
but there negatives don't
{$W no-unused} {$W no-unused-function} {$W no-unused-value} {$W no-unused-parameter} {$W no-unused-label} {$W no-unused-variable} {$W no-unused-function}
Unless I am doing something wrong (section 6.9 of the gpc manual), this seems to be an omission in gpc.
Regards,
Adriaan van Os