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/config.py

@@ -125,7 +125,7 @@ class SfgConfig(ConfigBase):
 
     c_interfacing: BasicOption[bool] = BasicOption(False)
     """If set to `True`, generates header files compatible for interfacing with C.
-    
+
     This will cause all definitions to be generated ``extern "C"``.
     """