Extend CPython C-API test to at least include (and thus parser) all .pxd files.

tests/run/cython_includes.pyx

@@ -4,6 +4,50 @@ from cpython cimport PyType_Check
 from cpython cimport PyType_Check as PyType_Check2
 from cpython.type cimport PyType_Check as PyType_Check3
 
+# Make sure we can cimport all .pxd files.
+cimport cpython.array
+cimport cpython.bool
+cimport cpython.buffer
+cimport cpython.bytearray
+cimport cpython.bytes
+cimport cpython.ceval
+cimport cpython.cobject
+cimport cpython.complex
+cimport cpython.datetime
+cimport cpython.dict
+cimport cpython.exc
+cimport cpython.float
+cimport cpython.function
+cimport cpython.getargs
+cimport cpython.instance
+cimport cpython.int
+cimport cpython.iterator
+cimport cpython.list
+cimport cpython.long
+cimport cpython.longintrepr
+cimport cpython.mapping
+cimport cpython.mem
+cimport cpython.method
+cimport cpython.module
+cimport cpython.number
+cimport cpython.object
+cimport cpython.oldbuffer
+cimport cpython.pycapsule
+cimport cpython.pylifecycle
+cimport cpython.pystate
+cimport cpython.pythread
+cimport cpython.ref
+cimport cpython.sequence
+cimport cpython.set
+cimport cpython.slice
+cimport cpython.string
+cimport cpython.tuple
+cimport cpython.type
+cimport cpython.unicode
+cimport cpython.version
+cimport cpython.weakref
+
+
 def libc_cimports():
     """
     >>> libc_cimports()
@@ -13,6 +57,7 @@ def libc_cimports():
     sprintf(buf, "%s", b'hello')
     print (<object>buf).decode('ASCII')
 
+
 def cpython_cimports():
     """
     >>> cpython_cimports()