Draft: C Interfacing

This MR enables C compatibility for the generated target code

• Adds SfgConfig.c_interfacing option that automatically marks all function declarations as extern "C"
• Provides hybrid compilation mode for header files where C/C++ includes and also function definitions are guarded by

#ifdef __cplusplus 
<cpp includes...>

#define EXTERNC extern "C"
#else 
<hybrid includes...>

#define EXTERN C
#endif

• Automatically converts C++ header includes, e.g. <cstdint>, to C compatible header includes, e.g. <stdint.h>, for hybrid mode

src/pystencilssfg/context.py

@@ -21,7 +21,7 @@ class SfgContext:
         self,
         header_file: SfgSourceFile,
         impl_file: SfgSourceFile | None,
-        c_interfacing: bool,
+        c_interfacing: bool = False,
         namespace: str | None = None,
         codestyle: CodeStyle | None = None,
         argv: Sequence[str] | None = None,