While attempting to do some stress-testing of npy_pkg_config.py, it was clear that a few broken things needed to be fixed (hopefully). I'd have to do some bisections to find out the last version that worked, but the current version in master does not appear to have a functional command-line interface, except for simple modules like npy_pkg_config.py mlib --version.

For instance npy_pkg_config.py --list-all raises ValueError: Expect package name on the command line:. But if npy_pkg_config.py mlib --list-all is run from "numpy/core/lib/npy-pkg-config", then the new error was __main__.PkgNotFound: Could not find file(s) ['mlib.ini.ini'].

Another change (which should be discussed here) is to explicitly run import numpy.core if pkgname == "numpy.core", which is necessary to run npy_pkg_config.py npymath. The error raised without this modification is ValueError: You should import numpy.core to get information on npymath. Other possibilities are to use importlib of pkgname.

The fixed behaviour for npy_pkg_config.py --list-all (here done on Windows) is:

> cd C:\Users\user\AppData\Local\Continuum\anaconda3\Lib\site-packages\numpy\core\lib\npy-pkg-config
> python D:\src\numpy\numpy\distutils\npy_pkg_config.py --list-all
mlib    mlib - Math library used with this version of numpy
npymath npymath - Portable, core math library implementing C99 standard

(same output of Linux, tested from wherever npy-pkg-config exists)

I've added a "TODO" comment to suggest that the --list-all should consider searching same directories as with the normal pkg_name behaviour.

I've done some stress-testing with options from both utilities on Linux and Windows and everything appears to behave the same as what's in the current master branch. I'd appreciate if anyone else can do some stress-testing too.

/azp run