uscan can created a repacked file based on d/copyright and I *think*
this is handled by devscripts. It invokes `xz' for compression without
the -T flag. Passing the -T argument with either 0 or 1 as the number of
CPUs has the following benefits:
- The actual compression is quicker if more than one CPU is available on
the compressing side.
- The actual decompression is quicker if more than one CPU is available
on the decompressing side. This requires that the compressor creates
multiple blocks while compressing.
I tried to fix this myself but I fail to find the right spot :/
Sebastian