Log Message:
Update to 2.6.1.

Prompted by beta.repology.org.

Changes from 2.6.0 to 2.6.1

     * Fixed a performance regression in some situations as consequence of
       increasing too much the BLOCK_SIZE1 constant. After more careful
       benchmarks (both in VML and non-VML modes), the value has been set
       again to 1024 (down from 8192). The benchmarks have been made with
       a relatively new processor (Intel Xeon E3-1245 v5 @ 3.50GHz), so
       they should work well for a good range of processors again.
     * Added NetBSD support to CPU detection. Thanks to Thomas Klausner.