BLD: include dll in package_data on Windows (#21321)

Author: chris-b1

doc/source/whatsnew/v0.23.1.txt

@@ -131,3 +131,4 @@ Bug Fixes
 **Other**
 
 - Tab completion on :class:`Index` in IPython no longer outputs deprecation warnings (:issue:`21125`)
+- Bug preventing pandas being used on Windows without C++ redistributable installed (:issue:`21106`)

setup.py

@@ -453,10 +453,10 @@ def pxd(name):
     return pjoin('pandas', name + '.pxd')
 
 
-# args to ignore warnings
 if is_platform_windows():
     extra_compile_args = []
 else:
+    # args to ignore warnings
     extra_compile_args = ['-Wno-unused-function']
 
 lib_depends = lib_depends + ['pandas/_libs/src/numpy_helper.h',
@@ -733,7 +733,7 @@ def pxd(name):
       maintainer=AUTHOR,
       version=versioneer.get_version(),
       packages=find_packages(include=['pandas', 'pandas.*']),
-      package_data={'': ['data/*', 'templates/*'],
+      package_data={'': ['data/*', 'templates/*', '_libs/*.dll'],
                     'pandas.tests.io': ['data/legacy_hdf/*.h5',
                                         'data/legacy_pickle/*/*.pickle',
                                         'data/legacy_msgpack/*/*.msgpack',