ENH Support path length > MAX_PATH=260 on Windows

[jeremiedbb]

Closes #181

• limit extended to 10 * MAX_PATH (2600)
• kept a hard limit for security reasons
• A warning is raised if a library has a path too long, and this lib is ignored

[jeremiedbb]

As discussed irl, setting up a test for this behavior seems overly complicated for such a very niche use case. Here's how it looks locally:

In [1]: from threadpoolctl import threadpool_info

In [2]: threadpool_info()
Out[2]: []

In [3]: import numpy

In [4]: threadpool_info()
Out[4]:
[{'user_api': 'blas',
  'internal_api': 'openblas',
  'num_threads': 16,
  'prefix': 'libscipy_openblas',
  'filepath': 'C:\\Users\\J\\miniconda3\\envs\\joblib-dev\\Lib\\site-packages\\numpy.libs\\libscipy_openblas64_-43e11ff0749b8cbe0a615c9cf6737e0e.dll',
  'version': '0.3.28',
  'threading_layer': 'pthreads',
  'architecture': 'Haswell'}]

In [5]: from ctypes import CDLL

# For the purpose of this local test I set the limit to a lower value than 2600 for convenience :) (but still higher than 260)
In [6]: CDLL("C:\\Users\\J\\R\\threadpoolctl\\aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      ⋮ aaaaaaaaaaaaaaaaaaaaaaaaaaa\\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
      ⋮ bbbbbbbbbbbbbbbbbb\\libopenblas_toooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
      ⋮ ooooooooooooooooooo_long.dll")
Out[6]: <CDLL 'C:\Users\J\R\threadpoolctl\aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\libopenblas_tooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo_long.dll', handle 7ffce4130000 at 0x22b7f1d08f0>

In [7]: threadpool_info()
C:\Users\J\R\threadpoolctl\threadpoolctl.py:1103: RuntimeWarning: Could not get the full path of a dynamic library (path too
long). This library will be ignored and threadpoolctl might not be able to control or display information about all loaded
libraries. Here's the truncated path: 'C:\\Users\\J\\R\\threadpoolctl
\aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\\libopenblas_toooooooooooooooooooooooooooooooooooooooooooooooooooooooooo'
  warnings.warn(
Out[7]:
[{'user_api': 'blas',
  'internal_api': 'openblas',
  'num_threads': 16,
  'prefix': 'libscipy_openblas',
  'filepath': 'C:\\Users\\J\\miniconda3\\envs\\joblib-dev\\Lib\\site-packages\\numpy.libs\\libscipy_openblas64_-43e11ff0749b8cbe0a615c9cf6737e0e.dll',
  'version': '0.3.28',
  'threading_layer': 'pthreads',
  'architecture': 'Haswell'}]

[ogrisel]

LGTM!