The message is reported for a pointer cast from 'char *' to 'char **' in the implementation of standard library macro ' va_start'. The cast is necessary in order to prevent the compiler from optimizing away the invocation of ' va_start'.
The cast is safe because the area pointed to by the destination pointer has the same size as the area pointed to by the source pointer (for the SMALL memory model, the size of a default data pointer is 1).