fix c compiler setup

[dstansby]

This is the change needed to fix the conda-forge build for numcodecs 0.13.0. Calling customize_compiler correctly sets up the Python paths on the compiler.

TODO:

• Unit tests and/or doctests in docstrings
• Tests pass locally
• Docstrings and API docs for any new/modified user-facing classes and functions
• Changes documented in docs/release.rst
• Docs build locally
• GitHub Actions CI passes
• Test coverage to 100% (Codecov passes)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.91%. Comparing base (8b53fc1) to head (69b6acc).
Report is 64 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #562   +/-   ##
=======================================
  Coverage   99.91%   99.91%           
=======================================
  Files          59       59           
  Lines        2339     2339           
=======================================
  Hits         2337     2337           
  Misses          2        2           

[jakirkham]

Thanks David! 🙏