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/composer/basic_composer.py

@@ -719,7 +719,7 @@ class SfgFunctionSequencer(SfgFunctionSequencerBase):
     def __call__(self, *args: SequencerArg) -> None:
         # check if header is in HYBRID mode for c_interfacing enabled
         if self._cursor.context.c_interfacing:
-            assert isinstance(self._cursor.context.header_file.file_type, SfgSourceFileType.HYBRID_HEADER)
+            assert self._cursor.context.header_file.file_type == SfgSourceFileType.HYBRID_HEADER
 
         """Populate the function body"""
         tree = make_sequence(*args)