sysstat: upgrade 12.7.5 -> 12.7.6

sysstat: upgrade 12.7.5 -> 12.7.6

Changelog:
==========
* sar/sadf: [A_NET_ETCP]: Rename retrans/s field to retrseg/s
  because it was already used in A_NET_NFS report.
* sadf: SVG: Fix oversized SVG canvas height.
* sadf: Don't cap SVG graph output at 100%.
* sadf: A_NET_SOFT: Don't display graphs for offline CPU.
* sadf: SVG: Don't ignore other views when one has to be skipped.
* sadf: Make sure structures will be alloacated for every installed CPU.
* sadf: Define MIN_CANVAS_HEIGHT constant.
* sar: Display min/max values only when available.
* Define macros for CPU manipulation.
* SREALLOC() macro: Make sure size is not zero.
* Fix a warning given by gcc v13 with -fanalyzer option.
* [Eli Schwartz]: configure.ac: fix erroneous bashisms.
* sar manual page updated.
* DTD and XSD documents updated.
* Year updated in copyright messages.
* Other cosmetic changes in code.
* FAQ and README files updated.
* Non regression tests updated. New tests added.

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>