nim project complains about missing src/ prefix in hybrid package
What am I doing wrong here?

`Prompt: Missing directory /Users/niv/.nimble/pkgs/neverwinter-1.1.1/src/neverwinter. Continue? [y/N]`

Package in question: https://github.com/niv/neverwinter.nim

The intent is to have a hybrid package that installs a bunch of binaries, but also ships the library the binaries use for other packages to import.

nimble file
```
import sequtils, ospaths, strutils

version       = "1.1.1"
author        = "Bernhard Stöckner <niv@nwnx.io>"
description   = "Neverwinter Nights 1 data accessor library and utilities"
license       = "MIT"

requires "nim >= 0.18.0"

srcDir = "src"
installDirs = @["neverwinter"]

binDir = "bin"
bin = listFiles("src").
  mapIt(it.splitFile.name).
  filterIt(it.startsWith("nwn_")).
  # There appears to be a compiler bug on 0.19.0 that segfaults it when
  # compiling nwn_net. So we skip it for 0.19.0.
  filterIt(NimVersion != "0.19.0" or it != "nwn_net")
```

output when installing or using
```
neverwinter.nim → master • nimble install
  Verifying dependencies for neverwinter@1.1.1
 Installing neverwinter@1.1.1
   Building neverwinter/nwn_resman_pkg using c backend
   Building neverwinter/nwn_key_pack using c backend
   Building neverwinter/nwn_tlk using c backend
   Building neverwinter/nwn_net using c backend
   Building neverwinter/nwn_erf using c backend
   Building neverwinter/nwn_resman_extract using c backend
   Building neverwinter/nwn_twoda using c backend
   Building neverwinter/nwn_key_transparent using c backend
   Building neverwinter/nwn_gff using c backend
   Building neverwinter/nwn_erf_tlkify using c backend
   Building neverwinter/nwn_resman_grep using c backend
   Building neverwinter/nwn_key_unpack using c backend
   Building neverwinter/nwn_resman_cat using c backend
   Building neverwinter/nwn_resman_diff using c backend
   Building neverwinter/nwn_key_shadows using c backend
   Building neverwinter/nwn_resman_stats using c backend
    Prompt: neverwinter@1.1.1 already exists. Overwrite? [y/N]
    Answer: y
    Prompt: Missing directory /Users/niv/.nimble/pkgs/neverwinter-1.1.1/src/neverwinter. Continue? [y/N]
    Answer: y
   Success: neverwinter installed successfully.
```

```
nwsync3 → packfiles • nimble build
  Verifying dependencies for nwsync3@0.1.3
      Info: Dependency on neverwinter@>= 1.1.1 already satisfied
    Prompt: Missing directory /Users/niv/.nimble/pkgs/neverwinter-1.1.1/src/neverwinter. Continue? [y/N]
    Answer: y
  Verifying dependencies for neverwinter@1.1.1
```