BLD: silence npy_no_deprecated warnings with numpy>=1.16.0 (pandas-dev#24864)

Author: jbrockmendel

setup.py

@@ -457,6 +457,11 @@ def run(self):
     directives['linetrace'] = True
     macros = [('CYTHON_TRACE', '1'), ('CYTHON_TRACE_NOGIL', '1')]
 
+# in numpy>=1.16.0, silence build warnings about deprecated API usage
+#  we can't do anything about these warnings because they stem from
+#  cython+numpy version mismatches.
+macros.append(('NPY_NO_DEPRECATED_API', '0'))
+
 
 # ----------------------------------------------------------------------
 # Specification of Dependencies