cURL package: add gssapi option (#11344)
cURL package: add gssapi option (#11344)

This option allows curl and its dependents (git, ...) to work with
proxy using Kerberos authentification.
LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,LLNL/spack,iulian787/spack,iulian787/spack,iulian787/spack,LLNL/spack