[PATCH v3] erofs-utils: use cmpsgn(x, y) for standardized large value comparsion

[Li Guifu]

> Previously, roundup(bb->buffers.off % EROFS_BLKSIZ, alignsize)
> + incr + extrasize is an unsigned 64bit value and sgn(x) didn't
> work properly. Fix it.
> 
> Fixes: b0ca535297b6 ("erofs-utils: support 64-bit internal buffer cache")
> Signed-off-by: Gao Xiang <hsiangkao at aol.com>
> ---

It looks good
Reviewed-by: Li Guifu <blucerlee at gmail.com>
Tested-by: Li Guifu <blucerlee at gmail.com>

Thanks,