Revert "debian/control.in/main: build-depends on debhelper (>= 12.5) to get automatic udeb support."
The debhelper changes had to be reverted due (see #934999)
This reverts commit 32ab7bcaed741549b0045694a72c206146aa0cb4.
debian/patches/git-updates.diff: update from upstream stable branch:
* debian/patches/git-updates.diff: update from upstream stable branch:
- Fix math tests on hppa.