Tony Stark has different armours for different foe, Spider-man has different gadgets and Batman is prepared for almost anything.
Surely supes has learnt from his weakness. What can he do against magic?
Against magic-using foes, Superman has limited options.
Typically, he will attempt to outthink his foes (such as Mytzlplk, who's powers may as well be magic).
If he can't outthink them, he relies on his allies (conveniently provided by team-up issues, or always present in group titles like JLA) who can combat magic effectively.
If the writers have stranded him, alone on foreign shores, against magical foes with none to aid him, he grits his teeth, poofs up his rockin' 90s mullet, and punches harder.