Merge branch 'dd/t9604-use-posix-timezones'

The cvsimport tests required that the platform understands traditional timezone notations like CST6CDT, which has been updated to work on those systems as long as they understand POSIX notation with explicit tz transition dates. * dd/t9604-use-posix-timezones: t9604: Fix test for musl libc and new Debian