os: Add system().

Author: pfalcon

os/metadata.txt

@@ -1,5 +1,5 @@
 srctype = micropython-lib
 type = package
-version = 0.1.2
+version = 0.1.3
 author = Paul Sokolovsky
 depends = libc

os/os/__init__.py

@@ -28,6 +28,7 @@
 _exit_ = libc.func("v", "_exit", "i")
 getpid_ = libc.func("i", "getpid", "")
 waitpid_ = libc.func("i", "waitpid", "ipi")
+system_ = libc.func("i", "system", "s")
 
 R_OK = const(4)
 W_OK = const(2)
@@ -167,6 +168,10 @@ def waitpid(pid, opts):
     check_error(r)
     return (r, a[0])
 
+def system(command):
+    r = system_(command)
+    check_error(r)
+    return r
 
 def fsencode(s):
     if type(s) is bytes:

os/setup.py

@@ -6,7 +6,7 @@
 
 
 setup(name='micropython-os',
-      version='0.1.2',
+      version='0.1.3',
       description='os module for MicroPython',
       long_description="This is a module reimplemented specifically for MicroPython standard library,\nwith efficient and lean design in mind. Note that this module is likely work\nin progress and likely supports just a subset of CPython's corresponding\nmodule. Please help with the development if you are interested in this\nmodule.",
       url='https://github.com/micropython/micropython/issues/405',

os/test_system.py

@@ -0,0 +1,4 @@
+import os
+
+print("Executing ls -l:")
+os.system("ls -l")