generator: add a find_libc library

Add a way to load the local standard C library.
This could be used to load some C standard functions, like *printf ones.

This should work on Linux, Windows and macOS/Darwin environments.

Author: garfvl

generator/templates/header.py

@@ -45,6 +45,7 @@
 import os
 import sys
 import functools
+import platform
 
 # Used by EventManager in override.py
 import inspect as _inspect
@@ -216,6 +217,22 @@ def find_lib():
 # plugin_path used on win32 and MacOS in override.py
 dll, plugin_path  = find_lib()
 
+def find_libc():
+    """Return an instance of the loaded standard C library or None if the
+       library has not been found.
+
+       This function should be compatible with Linux, Windows and macOS.
+    """
+    system = platform.system()
+    if system == 'Windows':
+        # On Windows, msvcrt provides MS standard C
+        return ctypes.cdll.msvcrt
+    elif system == 'Linux' or system == 'Darwin':
+        libc_path = find_library('c')
+        if libc_path is None:
+            return None
+        return ctypes.CDLL(libc_path)
+
 class VLCException(Exception):
     """Exception raised by libvlc methods.
     """