I'm not Windows development guru, so I'm not sure.
The DLLs are compiled with Microsoft Visual C++ with /LD switch (create DLL). I suspect, these DLLs are Cdecl because made with C/C++ without any additional settings.
Because LibRaw is distributed in open-source, you can easily modify it as you wish, including functions calling conventions.
I'm not Windows development guru, so I'm not sure.
The DLLs are compiled with Microsoft Visual C++ with /LD switch (create DLL). I suspect, these DLLs are Cdecl because made with C/C++ without any additional settings.
Because LibRaw is distributed in open-source, you can easily modify it as you wish, including functions calling conventions.