cmake: fix linking with GSL
cmake: fix linking with GSL

electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius,electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius,toxa81/sirius