WINAPI is for the windows calling convention to use, and should expand
to nothing on Linux.
https://build.gnome.org/continuous/buildmaster/builds/2017/07/18/76/build/log-gst-plugins-bad.txt
# else
# define CONVERT_COM_STRING(s) BSTR _s = (BSTR)s; s = _com_util::ConvertBSTRToString(_s); ::SysFreeString(_s);
# define FREE_COM_STRING(s) delete[] s;
-# endif
+# endif /* __MINGW32__ */
#else
#define COMSTR_T const char*
#define CONVERT_COM_STRING(s)
#define FREE_COM_STRING(s)
+#define WINAPI
#endif /* G_OS_WIN32 */
typedef enum {