CREATE TABLE table_55981 ("Name" TEXT, "Current version" TEXT, "System" TEXT, "Platform" TEXT, "License" TEXT)

What is the System when the Licence is gpl and the Current Version is 1.72?
SELECT "System" FROM table_55981 WHERE "License" = 'gpl' AND "Current version" = '1.72'
SELECT "System" FROM "table_55981" WHERE "Current version" = '1.72' AND "License" = 'gpl'