math/saga: Update to 9.12.2

Fixes a crash in the landsat_scene_import tool in GDALOpen(Ex)(),
when trying to open a non-existing file

Unfortunately, the tarball still contains many files with CRLF line
endings, so dos2unix is used again.

Changelog: https://sourceforge.net/p/saga-gis/wiki/Changelog%209.12.2/attachment/changelog_saga_9.12.2.txt