In Clang 3.4, the preferred (and new) option pattern is --target=. http://thread.gmane.org/gmane.comp.compilers.clang.devel/29975 http://llvm.org/viewvc/llvm-project?view=revision&revision=184408 Clang 3.4 is not yet released, but there is a release candidate, and there is a dashboard test of Clang trunk.