libostree v2017.13

[Colin Walters <walters verbum org>]

https://github.com/ostreedev/ostree/releases/tag/v2017.13

A lot of across-the-board improvements here; the pure bugfixes are mostly in the
experimental Avahi bits, hardening the `FIFREEZE` on `/boot` code, explicit
errors when trying to commit non-UTF8 filenames, and finally a number of fixes
around our use of `mmap`.

One slight backwards-incompatible change (but I doubt it'll break anyone):
`Disallow refs starting with a non-letter or digit`
If this *does* affect you, please let us know ASAP.
PR: https://github.com/ostreedev/ostree/pull/1286

For improvements, first up, Alex changed the static delta
code to avoid holding everything in memory; this is a substantial
improvement for large deltas, and also for flatpak which uses
deltas as a "bundle" format.
PR: https://github.com/ostreedev/ostree/pull/1309

A few notable changes:

`commit: Add _CONSUME modifier flag`
You probably want to use this by default for your build/package
systems.
PR: https://github.com/ostreedev/ostree/pull/1255

`core: Add standard SOURCE_TITLE metadata key`
This one I think is conceptually quite interesting; for many people, their
ostree commits are *derived* from something else that has its own versioning,
and it's useful to show that explicitly. I encourage ostree-based build systems
to consider rendering human-readable information about your builds into this
standardized metadata key.
PR: https://github.com/ostreedev/ostree/pull/1296

On the command line side, Ruixin Bao for cleaning
up the `--help` output significantly.
PR: https://github.com/ostreedev/ostree/pull/1267

And thanks to Simon McVittie for his regular fixups to the tests
to ensure they keep running in Debian!

Full shortlog below:

```
Alexander Larsson (4):
      Add OtVariantBuilder
      static deltas: Use OtVariantBuilder to create deltas
      static-delta-compilation: Move some things around
      static deltas: Process each part as soon as its done

Colin Walters (58):
      lib/commit: Add some gtk-doc and internal doc comments
      lib/sysroot: Add some more comments
      lib/pull: Fix regression with pull-local for nonexistent refs
      lib/syslinux: Port to fd-relative
      lib/uboot: Port to fd-relative
      lib/pull: Minor cleanup to metadata scanning function, add docs
      lib/core: Init struct stat buffer
      lib/sysroot: Fix pointer going out of scope in unlock code
      Deduplicate and fix up our use of mmap()
      lib/utils: Port a bit to decl-after-stmt style
      lib/pull: Change fetcher to return O_TMPFILE
      lib/util: Delete some unused functions
      lib/deltas: Move variant read helper into the deltas code
      commit: Add _CONSUME modifier flag
      lib: Add a lighter weight internal checksum wrapper
      lib/core: (refactor) Drop wrapper and unneeded args for variant writing
      lib/core: Port a few functions to decl-after-stmt
      lib/core: Use GBytes for file headers
      lib/commit: Make -path commit helper API private
      tree-wide: Update to new libglnx fd APIs
      lib/deploy: Use _exit() for FIFREEZE watchdog
      lib/deltas: Check cancellable during processing
      lib/pull: Drop duplicate/different error for GPG but no detached meta
      lib/pull: Also do commit GPG verification before writing
      tests/basic: Add missing ${COMMIT_ARGS} for bare-user-only
      lib/commit: Implement "adoption" with CONSUME flag
      lib: Use a common helper function to compare checksums
      lib/sysroot: Fix error handling when mounting overlayfs fails
      tests: Add test-pull-bareuseronly
      lib/deltas: Use fastpath for regfile writes for bare-user-only
      lib/deltas: Use pread() instead of lseek()+read()
      lib/commit: Avoid trying to delete `.` with _CONSUME flag
      lib/commit: Fix indentation in file commit code
      lib/commit: Use direct fd xattr operations again on regular files
      syntax-check: Add a rule to enforce glnx_autofd over glnx_fd_close
      lib/pull: Update summary checksum code to use new checksum API
      lib/repo: Update summary code to use newer hashing API
      lib/commit: (refactor) Clean up delta bare write API
      Disallow refs starting with a non-letter or digit
      lib/checkout: For "process whiteouts" mode, replace directories too
      repo: Add wrapper function for setting devino cache on checkout opts
      docs/related-projects: Add Google Usenix link
      bin/status: Port to new style
      bin/status: Inline metadata parsing for versions
      core: Add standard SOURCE_TITLE metadata key
      lib/commit: Fix hardlink checkout commit with bare-user + mod xattrs
      ci: Update centos container to current again
      tree-wide: Use autoptr for OstreeKernelArgs
      lib/repo: Fix loading commitstate with parent repos
      lib/deltas: Fix change to use pread() in write opcode
      lib: Minor static delta fixes
      lib/pull: When --require-static-deltas, use them even for file:/// repos
      lib/pull: Delete unused "exampleos" code
      bin/delta-compilation: Add a "progress bar" for bsdiff generation
      deltas: Add an if0'd bit to print bsdiff objects
      tests: Add a "pull-test2" that uses slightly more realistic content
      Update libglnx
      Release 2017.13

Dan Nicholson (4):
      lib/deploy: Ignore FIFREEZE/FITHAW errors when already in state
      build: Fix bsdiff Makefile circular dependency
      build: Do *.am.inc substitutions from make correctly
      lib/repo: Properly handle NULL homedir when signing commit

Jonathan Lebon (12):
      build-sys: Post-release version bump
      app/main: use HAVE_LIBCURL_OR_LIBSOUP for pull CLI
      ci: really turn on warnings
      tree: fix compiler warnings
      lib/commit: minor coverity fix
      libotutil/checksum-utils: fix openssl compilation
      ci: compile f26/c7-primary with libcurl/openssl
      tests: drop unused variable
      ostree/checksum: port to new decl style
      lib/core: add ostree_checksum_file_at API
      lib/checkout: fallback to checksum for UNION_IDENTICAL
      lib/commit: fix checking flag with bitwise OR

Marcus Folkesson (1):
      docs: mention the $OSTREE_REPO environment variable

Matthew Leeds (2):
      lib/gpg: Print debug info when reading GPG keys
      lib/utils: Check for invalid UTF-8 in filenames

Philip Withnall (10):
      lib/bloom: Add some missing preconditions on n_bytes
      lib/repo-commit: Import detached metadata even if hardlink exists
      docs: Clarify %NULL argument to ostree_sysroot_new()
      lib/repo: Clarify that ostree_repo_remote_fetch_summary() doesn’t verify
      lib/repo-finder-avahi: Fix a leak in a GVariantIter loop
      lib/repo-finder: Add OstreeRepoFinderOverride
      lib/sysroot: Expand docs for ostree_sysroot_get_repo()
      lib/repo-finder-avahi: Fix memory corruption of a GVariantIter
      lib/repo-finder-mount: Fix propagating NULL errors
      lib/repo-finder-mount: Ignore mounts which have a ‘system’ file system

Ruixin Bao (3):
      ostree: Describe subcommands in help output
      ostree: move flags into command struct, pass down through builtins
      ostree: provide command description in a better place

Shaun Taheri (1):
      static deltas: Set optional flag for superblock

Simon McVittie (3):
      Cope with xattr syscalls raising EOPNOTSUPP
      Make sure *.am.inc are up to date before `make dist`
      ostree-system-generator: Include <libglnx.h> for autocleanups
```

Git-EVTag-v0-SHA512: 
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