Hooks: numpy: Add hidden import numpy.core._dtype_ctypes.

PyInstaller/hooks/hook-numpy.py

@@ -44,11 +44,11 @@
 
 # PyInstaller can't detect imports from a cython or C extension module. If a
 # submodule is *only* ever `import`ed by a cython or C module then it wont be
-# found. Numpy currently has none of these. But should one be added, its string
-# name should be listed here. e.g. "numpy.core._hidden._guts._module".
+# found. Likewise __import__ and importlib are invisible to PyInstaller.
 # These issues should be very easy to track. You'll get a ModuleNotFoundError
-# for that hidden module at runtime if you forget to include one.
-hiddenimports = []
+# for that hidden module at runtime (usually straight away) if you forget to
+# include one.
+hiddenimports = ['numpy.core._dtype_ctypes']
 
 
 # --- Additional support for less official mkl builds ---