Remove conditional compilation handling old Python < 2.6

Cython/Compiler/TypeSlots.py

@@ -738,8 +738,8 @@ PyBufferProcs = (
     MethodSlot(segcountproc, "bf_getsegcount", "__getsegcount__", py3 = False),
     MethodSlot(charbufferproc, "bf_getcharbuffer", "__getcharbuffer__", py3 = False),
 
-    MethodSlot(getbufferproc, "bf_getbuffer", "__getbuffer__", ifdef = "PY_VERSION_HEX >= 0x02060000"),
-    MethodSlot(releasebufferproc, "bf_releasebuffer", "__releasebuffer__", ifdef = "PY_VERSION_HEX >= 0x02060000")
+    MethodSlot(getbufferproc, "bf_getbuffer", "__getbuffer__"),
+    MethodSlot(releasebufferproc, "bf_releasebuffer", "__releasebuffer__")
 )
 
 #------------------------------------------------------------------------------------------
@@ -809,7 +809,7 @@ slot_table = (
     EmptySlot("tp_subclasses"),
     EmptySlot("tp_weaklist"),
     EmptySlot("tp_del"),
-    EmptySlot("tp_version_tag", ifdef="PY_VERSION_HEX >= 0x02060000"),
+    EmptySlot("tp_version_tag"),
     EmptySlot("tp_finalize", ifdef="PY_VERSION_HEX >= 0x030400a1"),
 )
 

Cython/Includes/cpython/version.pxd

@@ -4,8 +4,8 @@
 #
 #      if PY_MAJOR_VERSION >= 3:
 #           do_stuff_in_Py3_0_and_later()
-#      if PY_VERSION_HEX >= 0x02060000:
-#           do_stuff_in_Py2_6_and_later()
+#      if PY_VERSION_HEX >= 0x02070000:
+#           do_stuff_in_Py2_7_and_later()
 #
 # than using the IF/DEF statements, which are evaluated at Cython
 # compile time.  This will keep your C code portable.

tests/run/ext_attribute_cache.pyx

@@ -11,9 +11,6 @@ cdef extern from *:
         unsigned long tp_flags
 
 
-SHOULD_HAVE_FLAG = PY_VERSION_HEX >= 0x02060000
-
-
 def test_flag(t):
     return ((<PyTypeObject*>t).tp_flags & Py_TPFLAGS_HAVE_VERSION_TAG) != 0
 
@@ -21,8 +18,7 @@ def test_flag(t):
 cdef class ImplicitAttrCache(object):
     """
     >>> flag = test_flag(ImplicitAttrCache)
-    >>> if SHOULD_HAVE_FLAG: print(flag)
-    ... else: print(True)
+    >>> print(flag)
     True
     """
     cdef public int x
@@ -33,8 +29,7 @@ cdef class ImplicitAttrCache(object):
 cdef class ExplicitAttrCache(object):
     """
     >>> flag = test_flag(ImplicitAttrCache)
-    >>> if SHOULD_HAVE_FLAG: print(flag)
-    ... else: print(True)
+    >>> print(flag)
     True
     """
     cdef public int x