[Backport pandas-dev#14496] BLD: Support Cython 0.25

closes pandas-dev#14496

(cherry picked from commit 66b4c83)

Author: robertwb

doc/source/whatsnew/v0.19.1.txt

@@ -33,7 +33,7 @@ Performance Improvements
 Bug Fixes
 ~~~~~~~~~
 
-
+- Compat with Cython 0.25 for building (:issue:`14496`)
 
 
 - Bug in localizing an ambiguous timezone when a boolean is passed (:issue:`14402`)

setup.py

@@ -85,7 +85,11 @@ def is_platform_mac():
 try:
     if not _CYTHON_INSTALLED:
         raise ImportError('No supported version of Cython installed.')
-    from Cython.Distutils import build_ext as _build_ext
+    try:
+        from Cython.Distutils.old_build_ext import old_build_ext as _build_ext
+    except ImportError:
+        # Pre 0.25
+        from Cython.Distutils import build_ext as _build_ext
     cython = True
 except ImportError:
     cython = False