internal/rosa: improve helper bindings

This uses more intuitive names for some arguments and inverts their default value. Slices and nil-capable strings replace skip arguments.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/package/lit.az

@@ -7,7 +7,7 @@ package lit {
 	exec = pip {
 		append = [ "llvm", "utils", "lit" ];
 		// already checked during llvm
-		skipCheck = true;
+		check = nil;
 	};
 
 	inputs = [ python-setuptools ];