Port to new build system, and adjust things to give the same output.
* 0030-fix-prefix-and-install-dir.patch: fixups for the new build system
* 0031-use-packaged-lempar.c.patch: patch from debian for the same thing we did
* 0002-sqlite3.32.3-Makefile.in-fix-rule-compiling-rbu.exe.patch: adjusted for the new build system
All other patches should no longer be needed.
Drop extensions that don't build for now.
