profiling vibe

[Jordan Wilson]

I can't seem to be able to use `--profile` with vibe:

```shell
dub init -t vibe.d
dub build --build=profile

../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(142,3): Warning: statement is not reachable
../../.dub/packages/vibe-core/2.7.3/vibe-core/source/vibe/internal/async.d-mixin-119(143,3): Warning: statement is not reachable
Error: warnings are treated as errors
        Use -wi if you wish to treat warnings only as 
informational.
```

I've tried using `buildRequirements "allowWarnings"`, but still 
the same.

Jordan