Add proof of concept Python binding

Supports this code:

widget: @python type
= {
    value: int;
    operator=: (out this, i: int) = { value = i; }

    add: (inout this, i: int) -> int
        = { value += i; return value; }

    shout: (this, s: std::string) -> std::string
        = s + "!";
}

Being invoked from Python like this:

import widgetlib

w = widgetlib.widget(10)
print(w.add(5))         # prints 15
print(w.add(i=7))       # prints 22
print(w.shout("hello")) # prints "hello!"

I'm not checking in a test case though because this is proof-of-concept only, currently hardwired to generate pybind11 and bash .sh invoking g++-10

Author: hsutter

regression-tests/test-results/version

@@ -1,4 +1,4 @@
 
-cppfront compiler v0.8.2 Build A815:1039
+cppfront compiler v0.8.2 Build A826:0706
 SPDX-License-Identifier  Apache-2.0 WITH LLVM-exception
 Copyright (c) 2022-2025  Herb Sutter

source/build.info

@@ -1 +1 @@
-"A815:1039"
+"A826:0706"

source/parse.h

@@ -6403,6 +6403,9 @@ class parser
 {
     std::vector<error_entry>& errors;
     std::set<std::string>&    includes;
+    std::vector<std::string>& extra_cpp1;
+    std::vector<std::string>& extra_build;
+    std::string               filename;
 
     std::unique_ptr<translation_unit_node> parse_tree = {};
 
@@ -6529,20 +6532,38 @@ class parser
     //
     parser( 
         std::vector<error_entry>& errors_,
-        std::set<std::string>&    includes_
+        std::set<std::string>&    includes_,
+        std::vector<std::string>& extra_cpp1_,
+        std::vector<std::string>& extra_build_,
+        std::string_view          filename_
     )
-        : errors{ errors_ }
-        , includes{ includes_ }
-        , parse_tree{std::make_unique<translation_unit_node>()}
+        : errors     { errors_ }
+        , includes   { includes_ }
+        , extra_cpp1 { extra_cpp1_ }
+        , extra_build{ extra_build_ }
+        , filename   { filename_ }
+        , parse_tree {std::make_unique<translation_unit_node>()}
     { }
 
     parser( parser const& that )
         : errors{ that.errors }
         , includes{ that.includes }
+        , extra_cpp1{ that.extra_cpp1 }
+        , extra_build{ that.extra_build }
         , parse_tree{std::make_unique<translation_unit_node>()}
     { }
 
 
+    //-----------------------------------------------------------------------
+    //  get_filename
+    //
+    auto get_filename() const
+        -> std::string
+    {
+        return filename;
+    }
+
+
     //-----------------------------------------------------------------------
     //  parse
     //