Workaround "clang not found" travis build error
Workaround "clang not found" travis build error

See https://github.com/travis-ci/travis-ci/issues/2607

glenwiley/getdns,glenwiley/getdns,shane-kerr/getdns,shane-kerr/getdns,shane-kerr/getdns,smogali/getdns,Acidburn0zzz/getdns,glenwiley/getdns,smogali/getdns,huitema/getdns,dkg/getdns,huitema/getdns,dkg/getdns,huitema/getdns,dkg/getdns,Acidburn0zzz/getdns,huitema/getdns,Acidburn0zzz/getdns,shane-kerr/getdns,dkg/getdns,smogali/getdns,Acidburn0zzz/getdns,glenwiley/getdns,smogali/getdns