This
https://sourceforge.net/projects/libxls/files/

I attempted to build the package several times but every time the hash
results to be wrong.

I correct it and then it's wrong again

For example, I get

@ build-failed
/gnu/store/dcaqrf007jxyi0jzlsakr3j7faxm122f-libxsl-1.4.0.tar.gz.drv - 1
output path
`/gnu/store/v6i85v3myb09nbsacq9ghx6yd0spcr67-libxsl-1.4.0.tar.gz' should
have sha256 hash `1574bcyagix5fkbs0yi2npi59y1zck23y2aia52vdv6ra3i5raid',
instead has `1zmsb0w6qh4vx7n7r3yijc5p4fwljyk5apzi1hwmrr5rkawmqmks'

so I change it to
1zmsb0w6qh4vx7n7r3yijc5p4fwljyk5apzi1hwmrr5rkawmqmks

and then I get

@ build-failed
/gnu/store/vsl7yz0nyklv0705jb5py015jkz3r6dg-libxsl-1.4.0.tar.gz.drv - 1
output path
`/gnu/store/wjyja461cr7kvvryp6v21q3iagf5rd8m-libxsl-1.4.0.tar.gz' should
have sha256 hash `1zmsb0w6qh4vx7n7r3yijc5p4fwljyk5apzi1hwmrr5rkawmqmks',
instead has `0fyd8h4i46qw3xii3pfa12k9k9ndmj59b552pmkpwcq7psyrbf32'

So now it's not 1zmsb0w6qh4vx7n7r3yijc5p4fwljyk5apzi1hwmrr5rkawmqmks
anymore. It's
0fyd8h4i46qw3xii3pfa12k9k9ndmj59b552pmkpwcq7psyrbf32

I'm doing this with a master checkout.

What am I missing ?