work around different NumPy 0.18 compile time configurations

tests/memoryview/relaxed_strides.pyx

@@ -26,6 +26,9 @@ See also:
 
 import numpy as np
 
+NUMPY_HAS_RELAXED_STRIDES = np.ones((10, 1), order="C").flags.f_contiguous
+
+
 
 def test_one_sized(array):
     """
@@ -33,7 +36,8 @@ def test_one_sized(array):
     >>> test_one_sized(contig)[0]
     1.0
     >>> a = np.arange(10, dtype=np.double)[::100]
-    >>> test_one_sized(a)[0]
+    >>> if NUMPY_HAS_RELAXED_STRIDES: print(test_one_sized(a)[0])
+    ... else: print(1.0)
     1.0
     """
     cdef double[::1] a = array
@@ -47,7 +51,7 @@ def test_zero_sized(array):
     >>> _ = test_zero_sized(contig)
 
     >>> a = np.arange(10, dtype=np.double)[100:200:10]
-    >>> _ = test_zero_sized(a)
+    >>> if NUMPY_HAS_RELAXED_STRIDES: _ = test_zero_sized(a)
     """
     cdef double[::1] a = array
     return a