Does not find python library even though it has correct path.

My Python executable is at: `/usr/nld/python-3.4.3-desktop/bin/python3`
The associated lib is at: `/usr/nld/python-3.4.3-desktop/lib/libpython3.4m.a`

I do:
```julia
julia> ENV["PYTHON"] = "/usr/nld/python-3.4.3-desktop/bin/python3"
"/usr/nld/python-3.4.3-desktop/bin/python3"

julia> Pkg.build("PyCall")
INFO: Building Conda
INFO: Building PyCall
===============================================[ ERROR: PyCall ]================================================

LoadError: Couldn't find libpython; check your PYTHON environment variable.

The python executable we tried was /usr/nld/python-3.4.3-desktop/bin/python3 (= version 3.4);
the library names we tried were String["libpython3.4m.a", "libpython3.4m", "libpython3.4", "libpython"]
and the library paths we tried were String["/usr/nld/python-3.4.3-desktop/lib", "/usr/nld/python-3.4.3-desktop/lib", "/usr/nld/python-3.4.3-desktop", "/usr/nld/python-3.4.3-desktop/lib"]
while loading /home/datseris/.julia/v0.6/PyCall/deps/build.jl, in expression starting on line 255

================================================================================================================

================================================[ BUILD ERRORS ]================================================

WARNING: PyCall had build errors.

- packages with build errors remain installed in /home/datseris/.julia/v0.6
- build the package(s) and all dependencies with `Pkg.build("PyCall")`
- build a single package by running its `deps/build.jl` script

================================================================================================================
```

which is weird, because the program states that it looks at the correct path *and* it has tried the correct name. Is there any way to fix? or any way to pass directly the library path like `ENV["PYTHONLIB"]` ?

Start by reproducing the PyCall build with ENV["PYTHON"] set to the executable in the report, then inspect deps/build.jl around line 255 and the reported library/path checks. Determine why the listed libpython3.4m.a is rejected, and consider the requested direct library-path configuration. Done means the build locates the supplied Python library and completes successfully.

Rédigé par le modèle d'indexation à partir du texte de l'issue.