Adds secp256k1 library dirs (#3962)
Adds secp256k1 library dirs (#3962)

int-index/stackage,Daniel-Diaz/stackage,mrkkrp/stackage,soenkehahn/stackage,jonschoning/stackage,mgajda/stackage,clinty/stackage,peti/stackage,ethercrow/stackage,wereHamster/stackage,fimad/stackage,stackbuilders/stackage,simonmichael/stackage,massysett/stackage,asr/stackage,spencerjanssen/stackage,athanclark/stackage,mstksg/stackage,iand675/stackage,fpco/stackage,michalkonecny/stackage,Shimuuar/stackage,creichert/stackage