--nimbleDir:someDir doesn't work if someDir is relative

[timotheecour]

nimble install -y --nimbleDir:build/deps_tmp2 opengl
    Prompt: No local packages.json found, download it from internet? -> [forced yes]
Downloading official package list
    Success Package list downloaded.
Downloading https://github.com/nim-lang/opengl using git
/Users/timothee/git_clone/nim/Nim_devel/lib/pure/includes/oserr.nim(94) raiseOSError
Error: unhandled exception: No such file or directory
Additional info: "build/deps_tmp2" [OSError]

nimble v0.11.0 compiled at 2020-04-04 14:23:52
git hash: 4007b2a

[timotheecour]

works in
nimble v0.12.0 compiled at 2020-11-14 00:30:46
git hash: 8f7af86