Convert all of our file methods to the CPython implementations

There's some low-hanging optimization fruit in here if we want to
(unnecessary crossings between Pyston and CAPI environments)
but we'll see.

src/runtime/capi.cpp

@@ -79,6 +79,10 @@ Box* BoxedWrapperDescriptor::__get__(BoxedWrapperDescriptor* self, Box* inst, Bo
     return new BoxedWrapperObject(self, inst);
 }
 
+extern "C" int PyObject_AsCharBuffer(PyObject* obj, const char** buffer, Py_ssize_t* buffer_len) noexcept {
+    Py_FatalError("unimplemented");
+}
+
 // copied from CPython's getargs.c:
 extern "C" int PyBuffer_FillInfo(Py_buffer* view, PyObject* obj, void* buf, Py_ssize_t len, int readonly,
                                  int flags) noexcept {

test/tests/thread_test.py

@@ -3,16 +3,20 @@ import time
 
 print type(allocate_lock())
 
+print_lock = allocate_lock()
+
 done = 0
 def run(arg):
     global done
+    with print_lock:
         print "in other thread!", arg
     done = 1
 
 
 print "starting!"
-t = start_new_thread(run, (5,))
-print type(t)
+with print_lock:
+    t = start_new_thread(run, (5,))
+    print type(t)
 
 while not done:
     time.sleep(0)