Add very basic implementation of os and fcntl modules for unix port.

Using ffi module. Both offer just 1-2 initial functions so far.

fcntl/fcntl.py

@@ -0,0 +1,23 @@
+import ffi
+
+
+libc = ffi.open("libc.so.6")
+
+fcntl_l = libc.func("i", "fcntl", "iil")
+fcntl_s = libc.func("i", "fcntl", "iis")
+ioctl_l = libc.func("i", "ioctl", "iil")
+ioctl_s = libc.func("i", "ioctl", "iis")
+
+
+def fcntl(fd, op, arg):
+    if type(arg) is int:
+        return fcntl_l(fd, op, arg)
+    else:
+        raise NotImplementedError
+
+
+def ioctl(fd, op, arg):
+    if type(arg) is int:
+        return ioctl_l(fd, op, arg)
+    else:
+        raise NotImplementedError

os/os.py

@@ -0,0 +1,14 @@
+import ffi
+
+
+libc = ffi.open("libc.so.6")
+
+errno = libc.var("i", "errno")
+mkdir_ = libc.func("i", "mkdir", "si")
+
+
+def mkdir(name, mode=0o777):
+    e = mkdir_(name, mode)
+    if not e:
+        return
+    raise OSError(errno.get())