BinDeps.jl does not find a package provided by conda-forge

[Alexander-Barth]

I have the following build.jl script which installs udunits2.

using BinDeps
using Conda


@BinDeps.setup
libudunits2 = library_dependency("libudunits2", aliases = ["udunits2","udunits"])

Conda.add_channel("conda-forge")
provides(Conda.Manager, "udunits2", libudunits2)
provides(AptGet, "libudunits2-dev", libudunits2, os = :Linux)
provides(Yum, "udunits2-devel", libudunits2, os = :Linux)

@BinDeps.install Dict(:libudunits2 => :libudunits2)

However, on windows, I get the following error:

[...]
The following packages will be SUPERSEDED by a higher-priority channel:
   conda:     4.3.30-py27h55876ee_0             --> 4.3.29-py27_0 conda-forge
   conda-env: 2.6.0-h36134e3_1                  --> 2.6.0-0       conda-forge
   openssl:   1.0.2m-h05bc326_1                 --> 1.0.2l-vc9_0  conda-forge [vc9]
   yaml:      0.1.7-h00170ee_2                  --> 0.1.6-vc9_0   conda-forge [vc9]
conda-env-2.6. 100% |###############################| Time: 0:00:00   0.00  B/s
openssl-1.0.2l 100% |###############################| Time: 0:00:00   5.26 MB/s
yaml-0.1.6-vc9 100% |###############################| Time: 0:00:00   0.00  B/s
expat-2.2.1-vc 100% |###############################| Time: 0:00:00   0.00  B/s
udunits2-2.2.2 100% |###############################| Time: 0:00:00   0.00  B/s
conda-4.3.29-p 100% |###############################| Time: 0:00:00  17.04 MB/s
===============================[ ERROR: UDUnits ]===============================
LoadError: Provider BinDeps.PackageManager failed to satisfy dependency libudunits2
while loading C:\Users\appveyor\.julia\v0.6\UDUnits\deps\build.jl, in expression starting on line 13

(full appveyor build log is here
https://ci.appveyor.com/project/Alexander-Barth/udunits-jl/build/job/oixfj4pyxa7vtlva)

On a Windows 10 laptop, I get the same error message. In Julia's conda folder I actually see a library udunits2.dll, but somehow this library is not found by BinDeps. BinDeps.debug("UDUnits") gives this:

INFO: Reading build script...
Warning: 'conda-forge' already in 'channels' list, moving to the top
The package declares 1 dependencies.
 - Library "libudunits2"
    - Providers:
      - Conda packages: udunits2
      - BinDeps.AptGet package libudunits2-dev (can't provide)
      - BinDeps.Yum package udunits2-devel (can't provide)

I use Julia 0.6.1, BinDeps 0.7.0 and Conda 0.7.0. No deps.jl file is generated. The Linux (using apt-get) and Mac (using conda too) build work fine.

[evetion]

Try to load the udunits2.dll as an absolute path with Libdl.dlopen(full_path). If that fails it will give a more sensible error message.