Add option to get rid of all CPP defaults at once

ctypesgen/__main__.py

@@ -192,13 +192,18 @@ def __call__(self, parser, namespace, values, option_string=None):
         help="Instruct the preprocessor to undefine the specified macro via commandline",
     )
     parser.add_argument(
-        "-X", "--no-default-cppflags",
+        "-X", "--pop-default-flags",
         nargs="+",
         action="extend",
         default=[],
         metavar="ENTRY",
         help="Remove ENTRY from preprocessor defaults, e.g. -X __GNUC__ can be used to not implicitly undefine __GNUC__.",
     )
+    parser.add_argument(
+        "--no-default-flags",
+        action="store_true",
+        help="Do not add any default defines/undefines at all. Beware: this will most probably lead to more parser errors."
+    )
     parser.add_argument(
         "--preproc-savepath",
         metavar="FILENAME",

ctypesgen/parser/preprocessor.py

@@ -61,7 +61,6 @@ def __init__(self, options, cparser):
         self.cparser = cparser  # An instance of CParser
 
         self.default_flags = {"-D": {}, "-U": []}
-
         self.default_flags["-D"].update({
             "__extension__": "",
             "__asm__(x)": "",
@@ -97,8 +96,11 @@ def __init__(self, options, cparser):
 
     def _get_default_flags(self):
 
+        if self.options.no_default_flags:
+            return {}
+
         flags_dict = copy.deepcopy(self.default_flags)
-        crossout = self.options.no_default_cppflags
+        crossout = self.options.pop_default_flags
         for params in flags_dict.values():
             deletor = params.pop if isinstance(params, dict) else params.remove
             unfound = []