fslx_open - open the file selector inside a window.
PROTOTYPAGE
void *fslx_open( char *title, int x, int y, int *handle,
char *path, int pathlen,
char *fname, int fnamelen,
char *patterns, XFSL_FILTER *filter,
char *paths, int sort_mode, int flags);
NOTES
This function is available when the bit AES4_FSLX of
app.aes4 is set to 1. If possible, FselInput() uses this
function to call the file selector.