Drop trailing separators when specifying dirs to compiler
Drop trailing separators when specifying dirs to compiler

Fixes #3801

Heather/Idris-dev,FranklinChen/Idris-dev,kojiromike/Idris-dev,Heather/Idris-dev,markuspf/Idris-dev,markuspf/Idris-dev,FranklinChen/Idris-dev,mpkh/Idris-dev,uuhan/Idris-dev,FranklinChen/Idris-dev,uuhan/Idris-dev,Heather/Idris-dev,Heather/Idris-dev,mpkh/Idris-dev,FranklinChen/Idris-dev,Heather/Idris-dev,markuspf/Idris-dev,markuspf/Idris-dev,uuhan/Idris-dev,markuspf/Idris-dev,uuhan/Idris-dev,kojiromike/Idris-dev,uuhan/Idris-dev,Heather/Idris-dev,markuspf/Idris-dev,kojiromike/Idris-dev,uuhan/Idris-dev,kojiromike/Idris-dev,markuspf/Idris-dev,mpkh/Idris-dev,FranklinChen/Idris-dev,mpkh/Idris-dev,uuhan/Idris-dev,FranklinChen/Idris-dev,kojiromike/Idris-dev,kojiromike/Idris-dev,mpkh/Idris-dev,mpkh/Idris-dev