upip: Capture recursive dependencies required for standalone running.

Also, improve package import handling.

upip/metadata.txt

@@ -2,6 +2,6 @@ srctype = micropython-lib
 type = module
 version = 0.1
 author = Paul Sokolovsky
-extra_modules = upip_errno, upip_gzip, upip_os, upip_os_path, upip_utarfile
+extra_modules = upip__libc, upip_errno, upip_gzip, upip_os, upip_os_path, upip_stat, upip_utarfile
 desc = Simple package manager for MicroPython.
 long_desc = Simple package manager for MicroPython, targetting to be self-hosted (but not yet there). Compatible only with packages without custom setup.py code.

upip/setup.py

@@ -15,4 +15,4 @@ setup(name='micropython-upip',
       maintainer='MicroPython Developers',
       maintainer_email='micro-python@googlegroups.com',
       license='MIT',
-      py_modules=['upip', 'upip_errno', 'upip_gzip', 'upip_os', 'upip_os_path', 'upip_utarfile'])
+      py_modules=['upip', 'upip__libc', 'upip_errno', 'upip_gzip', 'upip_os', 'upip_os_path', 'upip_stat', 'upip_utarfile'])

upip/upip.py

@@ -1,12 +1,20 @@
-def upip_import(mod):
+def upip_import(mod, sub=None):
     try:
-        return __import__("upip_" + mod)
+        mod_ = mod
+        if sub:
+            mod_ += "_" + sub
+        return __import__("upip_" + mod_)
     except ImportError:
-        return __import__(mod)
+        m = __import__(mod)
+        if sub:
+            return getattr(m, sub)
+        return m
 
 sys = upip_import("sys")
 os = upip_import("os")
-os.path = upip_import("os.path").path
+#os.path = upip_import("os.path").path
+ospath = upip_import("os", "path")
+
 errno = upip_import("errno")
 gzip = upip_import("gzip")
 try:
@@ -103,7 +111,7 @@ def install_pkg(pkg_spec, install_path):
     packages = data["releases"][latest_ver]
     assert len(packages) == 1
     package_url = packages[0]["url"]
-    package_fname = os.path.basename(package_url)
+    package_fname = ospath.basename(package_url)
     print(package_url)
     download(package_url, package_fname)