This update for libunwind fixes the following issues:

- Update to version 1.5.0. (jsc#ECO-3395)
- Enable s390x for building. (jsc#ECO-3395)
- Fix compilation with 'fno-common'. (bsc#1171549)
- Fix build with 'GCC-10'. (bsc#1160876)

This update was imported from the SUSE:SLE-15:Update update project.