Changes

Deliver 64-bit only pixz, enable testsuite
``` PASS: compress-file-permissions.sh SKIP: cppcheck-src.sh PASS:
single-file-round-trip.sh PASS: xz-compatibility-c-option.sh
============================================================================ 
Testsuite summary for pixz 1.0.6
============================================================================
# TOTAL: 4
# PASS:  3
# SKIP:  1
# XFAIL: 0
# FAIL:  0
# XPASS: 0
# ERROR: 0
============================================================================
```
`cppcheck-src.sh` test requires `cppcheck` which we don't have.
 (commit: 8587317)