Merge pull request RustPython#456 from yuvipanda/os-name

Implement os.name

Author: rmliddle

tests/snippets/os_info.py

@@ -0,0 +1,3 @@
+import os 
+
+assert os.name == 'posix'

vm/src/stdlib/os.rs

@@ -121,5 +121,13 @@ pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
     ctx.set_attr(&py_mod, "O_NONBLOCK", ctx.new_int(4));
     ctx.set_attr(&py_mod, "O_APPEND", ctx.new_int(8));
     ctx.set_attr(&py_mod, "O_CREAT", ctx.new_int(512));
+
+    if cfg!(windows) {
+        ctx.set_attr(&py_mod, "name", ctx.new_str("nt".to_string()));
+    } else {
+        // Assume we're on a POSIX system
+        ctx.set_attr(&py_mod, "name", ctx.new_str("posix".to_string()));
+    }
+
     py_mod
 }