template file when installed. The install
            prefix is always available through the variable ``@prefix@``, since the
            install prefix is not easy to get reliably from setup.py.

        See also
        --------
        add_installed_library, get_info

        Notes
        -----
        This works for both standard installs and in-place builds, i.e. the
        ``@prefix@`` refer to the source directory for in-place builds.

        Examples
        --------
        ::

            config.add_npy_pkg_config('foo.ini.in', 'lib', {'foo': bar})

        Assuming the foo.ini.in file has the following content::

            [meta]
            Name=@foo@
            Version=1.0
            Description=dummy description

            [default]
            Cflags=-I@prefix@/include
            Libs=

        The generated file will have the following content::

            [meta]
            Name=bar
            Version=1.0
            Description=dummy description

            [default]
            Cflags=-Iprefix_dir/include
            Libs=

        and will be installed as foo.ini in the 'lib' subpath.

        When cross-compiling with numpy distutils, it might be necessary to
        use modified npy-pkg-config files.  Using the default/generated files
        will link with the host libraries (i.e. libnpymath.a).  For
        cross-compilation you of-course need to link with target libraries,
        while using the host Python installation.

        You can copy out the numpy/core/lib/npy-pkg-config directory, add a
        pkgdir value to the .ini files and set NPY_PKG_CONFIG_PATH environment
        variable to point to the directory with the modified npy-pkg-config
        files.

        Example npymath.ini modified for cross-compilation::

            [meta]
            Name=npymath
            Description=Portable, core math library implementing C99 standard
            Version=0.1

            [variables]
            pkgname=numpy.core
            pkgdir=/build/arm-linux-gnueabi/sysroot/usr/lib/python3.7/site-packages/numpy/core
            prefix=${pkgdir}
            libdir=${prefix}/lib
            includedir=${prefix}/include

            [default]
            Libs=-L${libdir} -lnpymath
            Cflags=-I${includedir}
            Requires=mlib

            [msvc]
            Libs=/LIBPATH:${libdir} npymath.lib
            Cflags=/INCLUDE:${includedir}
            Requires=mlib

        N)