v("experimental-targets", "llvm.experimental-targets",
"experimental LLVM targets to build")
v("release-channel", "rust.channel", "the name of the release channel to build")
+v("release-description", "rust.description", "optional descriptive string for version output")
# Used on systems where "cc" is unavailable
v("default-linker", "rust.default-linker", "the default linker")