Update vendored windows libs

libs/win/bugs/multi_os_libc.py

@@ -0,0 +1,21 @@
+from ctypes import CDLL, c_char_p
+
+
+def get_libc():
+    libnames = ('msvcrt', 'libc.so.6')
+    for libname in libnames:
+        try:
+            return CDLL(libname)
+        except WindowsError:
+            pass
+        except OSError:
+            pass
+    raise RuntimeError("Unable to find a suitable libc (tried %s)" % libnames)
+
+
+getenv = get_libc().getenv
+getenv.restype = c_char_p
+
+# call into your linked module here
+
+print('new value is', getenv('FOO'))