{"action":"created","issue":{"url":"https://api.github.com/repos/LLNL/spack/issues/296","labels_url":"https://api.github.com/repos/LLNL/spack/issues/296/labels{/name}","comments_url":"https://api.github.com/repos/LLNL/spack/issues/296/comments","events_url":"https://api.github.com/repos/LLNL/spack/issues/296/events","html_url":"https://github.com/LLNL/spack/pull/296","id":124563822,"number":296,"title":"Make libunwind a no-op on non-linux architectures","user":{"login":"eschnett","id":213514,"avatar_url":"https://avatars.githubusercontent.com/u/213514?v=3","gravatar_id":"","url":"https://api.github.com/users/eschnett","html_url":"https://github.com/eschnett","followers_url":"https://api.github.com/users/eschnett/followers","following_url":"https://api.github.com/users/eschnett/following{/other_user}","gists_url":"https://api.github.com/users/eschnett/gists{/gist_id}","starred_url":"https://api.github.com/users/eschnett/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/eschnett/subscriptions","organizations_url":"https://api.github.com/users/eschnett/orgs","repos_url":"https://api.github.com/users/eschnett/repos","events_url":"https://api.github.com/users/eschnett/events{/privacy}","received_events_url":"https://api.github.com/users/eschnett/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":7,"created_at":"2016-01-01T22:22:08Z","updated_at":"2016-01-05T16:26:05Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/LLNL/spack/pulls/296","html_url":"https://github.com/LLNL/spack/pull/296","diff_url":"https://github.com/LLNL/spack/pull/296.diff","patch_url":"https://github.com/LLNL/spack/pull/296.patch"},"body":"libunwind requires ELF, and thus does not work on Windows or Darwin.\r\n\r\nMaking it a no-op allows requiring libunwind as dependency unconditionally in other packages."},"comment":{"url":"https://api.github.com/repos/LLNL/spack/issues/comments/169050440","html_url":"https://github.com/LLNL/spack/pull/296#issuecomment-169050440","issue_url":"https://api.github.com/repos/LLNL/spack/issues/296","id":169050440,"user":{"login":"eschnett","id":213514,"avatar_url":"https://avatars.githubusercontent.com/u/213514?v=3","gravatar_id":"","url":"https://api.github.com/users/eschnett","html_url":"https://github.com/eschnett","followers_url":"https://api.github.com/users/eschnett/followers","following_url":"https://api.github.com/users/eschnett/following{/other_user}","gists_url":"https://api.github.com/users/eschnett/gists{/gist_id}","starred_url":"https://api.github.com/users/eschnett/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/eschnett/subscriptions","organizations_url":"https://api.github.com/users/eschnett/orgs","repos_url":"https://api.github.com/users/eschnett/repos","events_url":"https://api.github.com/users/eschnett/events{/privacy}","received_events_url":"https://api.github.com/users/eschnett/received_events","type":"User","site_admin":false},"created_at":"2016-01-05T16:26:05Z","updated_at":"2016-01-05T16:26:05Z","body":"This means that every dependent needs to implement `detect_elf`.\r\n\r\nI'm not sure that the dependents actually care about whether the system is ELF; they will only care about whether libunwind is available or not. So maybe the function should be called `libunwind_exists`, as in: \"depend on libunwind if it exists, but don't depend on it if it doesn't exist\".\r\n\r\nNote that #299 also introduces a function `os_is_in`; I'm not sure this is useful (for reasons described there)."}}