Specify build requirements in pyproject.toml (PEP 517)

Author: xhochy

Diff for: MANIFEST.in

@@ -3,6 +3,7 @@ include LICENSE
 include RELEASE.md
 include README.md
 include setup.py
+include pyproject.toml
 
 graft doc
 prune doc/build

Diff for: doc/source/whatsnew/v0.25.0.rst

@@ -198,7 +198,7 @@ Sparse
 Other
 ^^^^^
 
--
+- Specify build-time requirement in ``pyproject.toml`` (:issue:`25193`)
 -
 -
 

Diff for: pyproject.toml

@@ -0,0 +1,3 @@
+# When changing the version numbers here, also adjust them in `setup.py`
+[build-system]
+requires = ["setuptools", "wheel", "cython >= 0.28.2", "numpy >= 1.12.0"]

Diff for: setup.py

@@ -17,6 +17,13 @@
 from distutils.version import LooseVersion
 from setuptools import setup, Command, find_packages
 
+# Taken from https://github.com/jupyterhub/traefik-proxy/commit/0f16dc307b72e613e71067b6498f82728461434a
+# ensure cwd is on sys.path
+# workaround bug in pip 19.0
+here = os.path.dirname(__file__)
+if here not in sys.path:
+    sys.path.insert(0, here)
+
 # versioning
 import versioneer
 cmdclass = versioneer.get_cmdclass()
@@ -30,6 +37,7 @@ def is_platform_mac():
     return sys.platform == 'darwin'
 
 
+# When changing the version numbers here, also adjust them in `pyproject.toml`
 min_numpy_ver = '1.12.0'
 setuptools_kwargs = {
     'install_requires': [