Fix

_build_utils.py

@@ -6,12 +6,13 @@
 from setuptools.command.build_py import build_py
 
 
-class NumpyImport(dict):
+class LazyImport(dict):
     """Hacky way to return Numpy's `include` path with lazy import."""
 
     # Must be json-serializable due to
     # https://github.com/cython/cython/blob/6ad6ca0e9e7d030354b7fe7d7b56c3f6e6a4bc23/Cython/Compiler/ModuleNode.py#L773
-    def __init__(self):
+    def __init__(self, module_name):
+        self.module_name = module_name
         return super().__init__(self, description=self.__doc__)
 
     # Must be hashable due to
@@ -20,9 +21,10 @@ def __hash__(self):
         return id(self)
 
     def __repr__(self):
-        import numpy as np
+        scope = {}
+        exec(f'import {self.module_name} as module', scope)
 
-        return np.get_include()
+        return scope['module'].get_include()
 
     __fspath__ = __repr__
 
@@ -53,8 +55,6 @@ def initialize_options(self):
 
 
 def get_ext_modules():
-    from pybind11.setup_helpers import Pybind11Extension
-
     name = 'imops'
     on_windows = platform.system() == 'Windows'
     args = ['/openmp' if on_windows else '-fopenmp']
@@ -73,7 +73,7 @@ def get_ext_modules():
         Extension(
             f'{name}.src._{prefix}{module}',
             [f'{name}/src/_{prefix}{module}.pyx'],
-            include_dirs=[NumpyImport()],
+            include_dirs=[LazyImport('numpy')],
             library_dirs=[NumpyLibImport()] if module in modules_to_link_against_numpy_core_math_lib else [],
             libraries=['npymath'] + ['m'] * (not on_windows)
             if module in modules_to_link_against_numpy_core_math_lib
@@ -88,10 +88,12 @@ def get_ext_modules():
         # for prefix, additional_args in zip(['', 'fast_'], [[], ['-ffast-math']])
         for prefix, additional_args in zip(['', 'fast_'], [[], []])
     ] + [
-        Pybind11Extension(
+        Extension(
             'cpp_modules',
             [f'{name}/cpp/src/main.cpp'],  # Sort source files for reproducibility
+            include_dirs=[LazyImport('pybind11')],
             extra_compile_args=args + cpp_args,
             extra_link_args=args + cpp_args,
+            language='c++',
         )
     ]